Phosphor incorporated in a thermal conductivity and phase transition heat transfer mechanism

RELATED APPLICATIONS

0001This application is related to U.S. Utility application Ser. No. 13/221,244 Filed Aug. 30, 2011 entitled “THERMAL CONDUCTIVITY AND PHASE TRANSITION HEAT TRANSFER MECHANISM INCLUDING OPTICAL ELEMENT TO BE COOLED BY HEAT TRANSFER OF THE MECHANISM.”

0002This application is related to U.S. Utility application Ser. No. 13/221,050 Filed Aug. 30, 2011 entitled “OPTICAL/ELECTRICAL TRANSDUCER USING SEMICONDUCTOR NANOWIRE WICKING STRUCTURE IN A THERMAL CONDUCTIVITY AND PHASE TRANSITION HEAT TRANSFER MECHANISM.”

TECHNICAL FIELD

0003The present subject matter relates to various thermal conductivity and phase transition heat transfer mechanisms that incorporate phosphor materials to be cooled by operation of the mechanisms.

BACKGROUND

0004Many different types of light emitting or generating devices utilize optically luminescent materials or ‘phosphors’ to produce a desired light output. Opto-luminescent phosphors may be excited in response to an optical input energy, and in response will re-emit light, although typically the spectral characteristic of the output light is somewhat different than the spectral characteristic of the input light. Phosphors tend to degrade over time due to exposure to heat. However, many applications for phosphor subject the phosphors to heat during device operation.

0005Consider a solid state lighting device, for a general lighting application, by way of an example. The solid state light sources typically produce light of specific limited spectral characteristics. To change or enhance the spectral characteristic of a solid state light source, for example, to obtain white light of a desired characteristic, one approach currently favored by LED (light emitting diode) manufacturers, utilizes a semiconductor emitter to pump phosphors within the device package (on or in close proximity to the actual semiconductor chip). Another approach uses one or more semiconductor emitters, but the phosphor materials are provided remotely (e.g. on or in association with a macro optical processing element such as a diffuser or reflector outside the semiconductor package). At least some opto-luminescent phosphors that produce desirable output light characteristics degrade quickly if heated, particularly if heated above a characteristic temperature limit of the phosphor material.

0006Hence, phosphor thermal degradation can be an issue of concern in many lighting systems. Thermal degradation of some types of phosphors may occur at temperatures as low as 85° C. Device performance may be degraded by 10-20% or more. The lifecycle of the phosphor may also be adversely affected by temperature.

0007At least some of the recently developed semiconductor nanophosphors and/or doped semiconductor nanophosphors may have an upper temperature limit somewhere in the range of 60-80° C. The light conversion output of these materials degrades quickly if the phosphor material is heated to or above the limit, particularly if the high temperature lasts for a protracted period.

0008Maintaining performance of the phosphors therefore creates a need for efficient dissipation of any heat produced during light generation. A current mitigation technique for phosphor thermal degradation is to maintain separation of the phosphor from the heat source and maximize unit area of phosphor to minimize flux density. However, the need for more lumens in an output using the phosphor requires larger phosphor unit area, and any limits placed on the flux density to reduce thermal impact on the phosphor constrains the overall device design.

0009For equipment utilizing phosphors, there is a continuing need for ever more effective dissipation of heat. Improved heat dissipation may provide a longer operating life for the apparatus or device using the phosphor(s). Improved heat dissipation may allow a device to drive the phosphor harder, to emit more light, for a particular application.

0010Many thermal strategies have been tried to dissipate heat from and cool active optical elements, including those that have or are combined with phosphors. Many systems or devices use a heat sink to receive and dissipate heat from the hot system component(s) during operation. A heat sink is a component or assembly that transfers generated heat to a lower temperature medium. Although the lower temperature medium may be a liquid, the lower temperature medium often is air.

0011A larger heat sink with more surface area dissipates more heat to the ambient atmosphere. However, there is often a tension or trade off between the size and effectiveness of the heat sink versus the commercially viable size of the device that must incorporate the sink. For example, if a solid state lamp must conform to the standard form factor of an A-lamp to be a commercially viable product, then that form factor limits the size of the heat sink. To improve thermal performance for some applications, an active cooling element may be used, to dissipate heat from a heat sink or from another thermal element that receives heat from the active system element(s) generating the heat. Examples of active cooling elements include fans, Peltier devices, membronic cooling elements and the like.

0012Other thermal strategies for equipment have utilized heat pipes or other devices based on principles of a thermal conductivity and phase transition heat transfer mechanism. A heat pipe or the like may be used alone or in combination with a heat sink and/or an active cooling element.

0013A device such as a heat pipe relies on thermal conductivity and phase transition of a working fluid between evaporation and condensation to transfer heat between two interfaces. Such a device includes a vapor chamber and working fluid within the chamber, typically at a pressure somewhat lower than atmospheric pressure. The working fluid, in its liquid state, contacts the hot interface where the device receives heat input. As the liquid absorbs the heat, it vaporizes. The vapor fills the otherwise empty volume of the chamber. Where the chamber wall is cool enough (the cold interface), the vapor releases heat to the wall of the chamber and condenses back into a liquid. Thermal conductivity at the cold interface allows heat transfer away from the mechanism, e.g. to a heat sink or to ambient air. By gravity or a wicking structure, the liquid form of the fluid flows back to the hot interface. In operation, the working fluid goes through this evaporation, condensation and return flow to form a repeating thermal cycle that effectively transfers the heat from the hot interface to the cold interface. Devices like heat pipes can be more effective than passive elements like heat sinks, and they do not require power and/or mechanical moving parts as do active cooling elements. It is best to get the heat away from the active optical element and any other sensitive components such as a phosphor as fast as possible, and the heat pipe improves heat transfer away from the active optical element, even where transferring the heat to other heat dissipation elements.

0014Although these prior technologies do address the thermal issues somewhat, there is still room for further improvement, particularly with regard to thermal issues effecting the phosphor or phosphors in light emitting systems.

0015For example, passive cooling elements, active cooling elements and heat transfer mechanisms that rely on thermal conductivity and phase transition have been implemented outside of the devices that incorporate active optical elements and separate and apart from any phosphor that may be included in the light emitting system. A light processing device may include one or more elements coupled to the actual system element that generates the heat, to transfer heat to the external thermal processing device. Of note, these devices, cooling elements and related thermal mitigation strategies have not been specifically adapted to the cooling of phosphors.

0016There is an increasing desire for higher, more efficient operation (light output or response to light input) in ever smaller packages. As outlined above, thermal capacity may require control of heat at the phosphor level. Hence, it may be advantageous to improve technologies to more effectively dissipate heat from and/or around phosphor materials.

SUMMARY

0017The teachings herein alleviate one or more of the above noted problems and provide improvements in thermal mitigation of phosphors used in systems for generating light.

0018For example, a lighting device may include an opto-luminescent phosphor of a type excited by optical energy of a first spectral characteristic to emit light of a second spectral characteristic different from the first spectral characteristic. The lighting device also includes a source of optical excitation energy, for supplying the optical excitation energy to the phosphor. A housing has a section that is thermally conductive and a member that is at least partially optically transmissive, for allowing emission of light emitted from the phosphor as an output of the lighting device. The optically transmissive member is connected to the thermally conductive section of the housing to form a seal for a vapor tight chamber. The phosphor is contained within the chamber. The lighting device also includes a working fluid within the chamber. The pressure within the chamber configures the working fluid to absorb heat during operation of the lighting device, to vaporize at a relatively hot location at or near at least a portion of the opto-luminescent phosphor as the working fluid absorbs heat, to transfer heat to and condense at a relatively cold location, and to return as a liquid to the relatively hot location. The working fluid is in direct contact with or contains at least a portion of the opto-luminescent phosphor.

0019A variety of examples of phosphor configurations are discussed below and illustrated in the drawings. For example, the phosphor may be in a coating layer within the chamber, e.g. on a surface of the optically transmissive member. If a wicking structure is provided, the phosphor may be in or form part of the wicking structure, e.g. in the form of phosphor bearing nanowires that form at least part of the wicking structure. In other examples, the working fluid carries the phosphor.

0020Examples are considered in which the source is outside the lighting device and coupled to supply the optical excitation energy through an optically transmissive member to excite the phosphor. This member may be same as or in addition to the member through which re-emitted light from the phosphor is output from the device.

0021In other examples, the source is inside the chamber as well. For example, the source may be a semiconductor device of an appropriate type within the chamber that is also cooled by the thermal cycle of the working fluid. In several examples, the semiconductor light emitter includes semiconductor nanowires, which may serve as part of a wicking structure as well.

0022In the examples, the thermal cycle of the working fluid within the chamber transfers heat away from some or all of the excited phosphor. This improved heat transfer helps mitigate thermal degradation of the phosphor.

0023Additional advantages and novel features will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The advantages of the present teachings may be realized and attained by practice or use of various aspects of the methodologies, instrumentalities and combinations set forth in the detailed examples discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

0024The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements.

0025<figref idref="DRAWINGS">FIG. 1</figref> is a cross-sectional view of an example of a thermal conductivity and phase transition heat transfer mechanism that incorporates a phosphor within the thermal conductivity and phase transition heat transfer mechanism.

0026<figref idref="DRAWINGS">FIGS. 2A-2E</figref> are various views of an example of a light emitting device or light engine, having a source and a thermal conductivity and phase transition heat transfer mechanism that incorporates a phosphor within the thermal conductivity and phase transition heat transfer mechanism.

0027<figref idref="DRAWINGS">FIG. 3</figref> is a cross-sectional view of an example of a light fixture incorporating a light engine like that shown in <figref idref="DRAWINGS">FIG. 2B</figref>.

0028<figref idref="DRAWINGS">FIG. 4</figref> is a comparative diagram useful in explaining how reducing the size and increasing the number of thermal elements per unit area increases the surface area for heat transfer and reduces the thermal resistance, and thus shows the advantages of using nanowires or similarly sized elements in the wicking structure of a thermal conductivity and phase transition heat transfer mechanism.

0029<figref idref="DRAWINGS">FIG. 5</figref> is a side view of an example of a lamp, for lighting applications, which uses solid state light emitters and a phosphor in a thermal conductivity and phase transition heat transfer mechanism to produce white light.

0030<figref idref="DRAWINGS">FIG. 6</figref> is a cross-sectional view of an example of the lamp of <figref idref="DRAWINGS">FIG. 5</figref>, taken along line <b>6</b>-<b>6</b> of <figref idref="DRAWINGS">FIG. 5</figref>.

0031<figref idref="DRAWINGS">FIG. 7</figref> is an enlarged detailed view of the portion of the lamp cross-section encompassed by the oval <b>7</b> in <figref idref="DRAWINGS">FIG. 6</figref>, showing the thermal conductivity and phase transition heat transfer mechanism and the coupling thereof to the heat sink.

0032<figref idref="DRAWINGS">FIG. 8</figref> is a still further enlarged detailed view of the portion of lamp cross-section encompassed by the circle <b>8</b> in <figref idref="DRAWINGS">FIG. 7</figref>, showing portions of the walls and wicks for the thermally conductive housing section and the optically transmissive members.

0033<figref idref="DRAWINGS">FIG. 9</figref> is a cross-sectional view of an alternate example of a thermal conductivity and phase transition heat transfer mechanism which may be used with other components similar to those of <figref idref="DRAWINGS">FIGS. 5 and 6</figref> to form a lamp.

0034<figref idref="DRAWINGS">FIGS. 10</figref>, <b>11</b> and <b>12</b> are top, isometric and side/plan views of a light emitting device with emitters, a mechanism containing phosphor, a heat sink and passive optical elements, for use in a fixture or lamp/light bulb for a more directed lighting application.

0035<figref idref="DRAWINGS">FIG. 13A</figref> is a cross-sectional view taken along line A-A of <figref idref="DRAWINGS">FIG. 12</figref>.

0036<figref idref="DRAWINGS">FIG. 13B</figref> is an enlarged detail view of a portion of the thermal conductivity and phase transition heat transfer mechanism that incorporates the phosphor and a portion of the optic, encircled by the arrow B in <figref idref="DRAWINGS">FIG. 13A</figref>.

0037<figref idref="DRAWINGS">FIGS. 14 and 15</figref> are top and isometric views of another example of a light emitting device and heat sink as may be used in a fixture or lamp/light bulb.

0038<figref idref="DRAWINGS">FIG. 16A</figref> is a cross-sectional view taken along line A-A of <figref idref="DRAWINGS">FIG. 14</figref>.

0039<figref idref="DRAWINGS">FIG. 16B</figref> is an enlarged detail view of a portion of the thermal conductivity and phase transition heat transfer mechanism that incorporates the phosphor, encircled by the arrow B in <figref idref="DRAWINGS">FIG. 16A</figref>, which also shows the phosphor layer.

0040<figref idref="DRAWINGS">FIG. 17</figref> is an enlarged detailed view of a portion of the semiconductor transducer in the apparatus of <figref idref="DRAWINGS">FIG. 16B</figref>, including a number of the semiconductor nanowires of the wick.

0041<figref idref="DRAWINGS">FIGS. 18 and 19</figref> are top and isometric views of another light emitting device and heat sink as may be used in a fixture or lamp/light bulb.

0042<figref idref="DRAWINGS">FIG. 20A</figref> is a cross-sectional view taken along line A-A of <figref idref="DRAWINGS">FIG. 18</figref>.

0043<figref idref="DRAWINGS">FIG. 20B</figref> is an enlarged detail view of a portion of the thermal conductivity and phase transition heat transfer mechanism that incorporates the phosphor, encircled by the arrow B in <figref idref="DRAWINGS">FIG. 20A</figref>.

DETAILED DESCRIPTION

0044In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

0045The various technologies disclosed herein relate to apparatuses, devices or systems for emitting light which utilize a phosphor, where the phosphor is included in the chamber of a cooling element such as a thermal conductivity and phase transition heat transfer mechanism. A variety of examples of such arrangements as well as techniques for making and operating such mechanisms, etc., that so include the phosphor, are discussed below.

0046For example, a thermal conductivity and phase transition heat transfer mechanism may have an opto-luminescent phosphor contained within the vapor chamber of the mechanism. Such a mechanism includes a housing having a section that is thermally conductive and at least one member that is at least partially optically transmissive. The optically transmissive member is connected to the thermally conductive section of the housing to form a seal for a vapor tight chamber. The mechanism also includes the opto-luminescent phosphor contained within the chamber for emitting light through the optically transmissive member when the phosphor is excited. A working fluid also is contained within the chamber. The pressure within the chamber configures the working fluid to absorb heat during operation of the lighting device, to vaporize at a relatively hot location at or near at least a portion of the opto-luminescent phosphor as the working fluid absorbs heat including heat from at least some of the phosphor. The vapor transfers heat to and condenses at a relatively cold location, and the vapor returns as a liquid to the relatively hot location. Also, the working fluid is in direct contact with or contains at least a portion of the opto-luminescent phosphor.

0047A lighting device, system or apparatus would include a mechanism like that outlined above, typically in combination with a source of optical energy for exciting the phosphor within the chamber. The source may be in the chamber as well, or the source may be outside the chamber and coupled to supply light to the phosphor within the chamber through an optically transmissive member.

0048The phase transition heat transfer via the thermal cycle of the working fluid more efficiently transfers heat produced during operation of the lighting device away from the excited phosphor. For example, at least some of the phosphor is directly exposed to the working fluid, without any additional intervening members, layers or interfaces that might otherwise impede the transfer of heat from the phosphor to the working fluid. The improved efficiency of the heat transfer and dissipation via the thermal conductivity and phase transition heat transfer mechanism may improve the operations and/or operational life of the semiconductor transducer. For example, it may be possible to operate the device using the phosphor at higher light or electrical power, and thus increase the excitation of the phosphor, without adverse impact on the performance or life of the phosphor.

0049Reference now is made in detail to the examples illustrated in the accompanying drawings and discussed below. <figref idref="DRAWINGS">FIG. 1</figref> is a cross-sectional view of an example of a thermal conductivity and phase transition heat transfer mechanism <b>1</b> that incorporates a phosphor material. In this first example, the source of energy to pump or excite the phosphor is not included inside the mechanism and is omitted for ease of illustration and discussion. Later drawings show examples with the source outside the mechanism and as well as examples with the source inside the mechanism.

0050The mechanism <b>1</b> includes a housing <b>3</b>. The housing <b>3</b> has at least one section that is thermally conductive. In the example of <figref idref="DRAWINGS">FIG. 1</figref>, the major section <b>5</b> of the housing <b>3</b> is formed of a thermally conductive material. Examples of suitable materials include metals, such as copper and aluminum, although other thermally conductive material materials, such as thermally conductive plastics and ceramics, may be used form manufacture the housing section <b>5</b>.

0051The housing <b>3</b> has at least one member <b>9</b> that is at least partially optically transmissive. The first example of a mechanism includes two members <b>9</b> and <b>10</b>, each of which is at least partially optically transmissive. Each optically transmissive member <b>9</b> or <b>10</b> may be transparent or translucent or exhibit other transmissive characteristics (e.g. non-white color filtering), depending on the optical requirements of the particular application of the mechanism <b>1</b>. In an example like that of <figref idref="DRAWINGS">FIG. 1</figref>, in which the mechanism does not incorporate the source, at least one of the optically transmissive members <b>9</b>, <b>10</b> would allow entry of optical energy from an external source, whereas one or both of the optically transmissive members <b>9</b>, would allow emission of light as an output. The optically transmissive members <b>9</b> and <b>10</b> appear flat in cross-section, although they could have other shapes, e.g. convex or concave, if a particular shape would promote light input or light output for a particular application.

0052If the apparatus <b>1</b> is cylindrical, then when viewed from either end, the apparatus <b>1</b> would appear circular. Either member <b>9</b> or member <b>10</b> could be circular or have other shapes, even in a cylindrical implementation of the apparatus <b>1</b>. Those skilled in the art will appreciate that the lateral shapes of the mechanism as a whole and of the optically transmissive member(s) may take other geometric forms, such as oval, rectangular or square, just to name a few examples.

0053The material forming each optically transmissive member <b>9</b> or <b>10</b> may be any material of sufficient optical transmissivity that is also able to withstand the expected operating temperatures of the mechanism <b>1</b>. Examples of suitable materials for the members <b>9</b>, <b>10</b> include various forms of glass ceramics and plastics. The material of the optically transmissive members <b>9</b>, <b>10</b> may or may not need to be heat resistant, depending on the temperature at the location of each member during operation. Each optically transmissive member <b>9</b> or <b>10</b> is connected to the housing section <b>5</b> to form a seal for a vapor tight chamber <b>11</b> enclosed by the thermally conductive housing section <b>5</b> and the optically transmissive members <b>9</b>, <b>10</b>. The material of the member <b>9</b> or <b>10</b> is sufficiently transmissive to light, at least in the portion of the optical energy spectrum that is relevant to operations of the mechanism <b>1</b>, so as to allow passage of optical energy into and/or out of the apparatus <b>1</b>.

0054As noted, the optically transmissive members <b>9</b>, <b>10</b> are attached to the housing section <b>5</b> to form a seal for a vapor tight chamber <b>11</b>. For example, if the optically transmissive members <b>9</b>, <b>10</b> are formed of a glass or ceramic material and the housing section <b>5</b> is formed of a metal, the different elements may be joined by a glass frit process or by application of a suitable epoxy.

0055An active optical element converts energy from one form or another by an electrical process and/or an excitation state change process, where at least one form of the energy is optical, e.g. light. Active optical elements include optically driven elements, such as optically pumped phosphors and electrical devices driven by light to produce electricity, as well as electrical devices and/or phosphors driven by electricity or electrical/electromagnetic fields to produce light. By contrast, passive optical elements process and even change the character of light, but by optical processing only, that is to say without use of an electrical and/or excitation state change process. Examples of passive optical elements include windows, lenses, optical color filters, reflectors, gratings, diffusers, and the like.

0056The mechanism or device <b>1</b> also includes an opto-luminescent phosphor <b>17</b> contained within the chamber for emitting light, when excited by optical pumping energy. The phosphor <b>17</b> is the active optical element of the mechanism or device <b>1</b>. In some of the later examples, other active optical elements, in addition to the phosphor, are provided within the chamber <b>11</b> of the apparatus <b>1</b>. As discussed more later, light emitted by the excited phosphor <b>17</b> is output from the mechanism via one or both of the optically transmissive members <b>9</b>, <b>10</b>. The heat transfer function of the mechanism <b>1</b> mitigates thermal impact on the phosphor <b>17</b>.

0057A portion of the housing section <b>5</b> will form a cold location <b>7</b> within the chamber <b>11</b>, for example, acting as or coupled to a heat sink (not separately shown). In the example of <figref idref="DRAWINGS">FIG. 1</figref>, a cold location <b>7</b> is formed near an end portion of the thermally conductive housing section <b>5</b> and the second optically transmissive member <b>10</b>. Of course, any heat sink coupled to the mechanism at or near the cold location would not optically block passage of light to/from the optically transmissive member <b>10</b> in this example.

0058The exemplary apparatus <b>1</b> also includes a working fluid within the chamber <b>11</b>. The pressure within the chamber <b>11</b>, typically a pressure somewhat lower than atmospheric pressure, configures the working fluid to absorb heat during operation of the apparatus, to vaporize at a relatively hot location <b>13</b> as it absorbs heat, to transfer heat to and condense at the relatively cold location <b>7</b>, and to return as a liquid to the relatively hot location. A variety of different fluids may be used as the working fluid, and the pressure is determined based on the fluid type and the amount of heat that the fluid is expected to transfer.

0059The working fluid, in its liquid state, contacts the hot interface at the location <b>13</b> where the apparatus receives or produces heat. In the example, the working fluid directly contacts at least some surface area(s) of the phosphor layer <b>17</b> at or near the hot location <b>13</b>. At those surface areas, the working fluid absorbs at least some heat from the phosphor, be it heat generated by excitation of the phosphor or heat the phosphor may receive from the external excitation source.

0060As the liquid absorbs the heat, it vaporizes. The vapor fills the otherwise empty volume of the chamber <b>11</b>. Where the chamber wall is cool enough (the cold interface at location <b>7</b>), the vapor releases heat to the wall of the chamber <b>11</b> and condenses back into a liquid. The drawing shows a central arrow from the hot location <b>13</b> toward the cold location <b>7</b>. This arrow generally represents the flow of heat in the vapor from the hot location <b>13</b> where the working fluid vaporizes toward the cold location <b>7</b> where the working fluid transfers heat for output via the thermally conductive housing section <b>5</b> and condenses back to the liquid form. The liquid form of the fluid flows back to the hot interface at location <b>13</b>. The drawing shows arrows generally along the outer wall(s) of the housing from the relatively cold location <b>7</b> back to the relatively hot location <b>13</b>. The arrows generally represent the flow of the condensed working fluid from the relatively cold location <b>7</b> back to the relatively hot location <b>13</b> where the fluid again vaporizes as it absorbs heat. In operation, the working fluid goes through this evaporation, condensation and return flow to form a repeating thermal cycle that effectively transfers the heat from the hot interface at location <b>13</b> to the cold interface at location <b>7</b>.

0061The device <b>1</b> in the example thus is configured as a thermal conductivity and phase transition heat transfer mechanism, similar to many mechanisms which are sometimes referred to as “heat pipes.” The thermal conductivity of the housing section <b>5</b> and the phase transition cycle through evaporation and condensation transfer heat from the hot location <b>13</b> to the cold location <b>7</b>. Thermal conductivity at the cold interface allows heat transfer away from the mechanism, e.g. to a heat sink or to ambient air. Active cooling may also be provided. The configuration of the mechanism together with the degree of cooling determine the internal operating temperature, e.g. at the hot location <b>13</b>. For example, the mechanism and a heat sink may support a maximum internal operating temperature around 50° C. Addition of active cooling or refrigeration at the cold interface may enable operation at a much lower internal temperature, such as 0° C.

0062Although some thermal conductivity and phase transition heat transfer mechanisms do not include a wicking structure, the exemplary mechanism <b>1</b> also includes a wicking structure <b>15</b> mounted within the chamber <b>11</b> to facilitate the flow of condensed liquid of the working fluid from the cold location <b>7</b> to the hot location <b>13</b> of the mechanism <b>1</b>. Capillary action or “wicking” relies on inter-molecular forces between a liquid and the surface(s) of a material around the liquid to cause movement of the liquid along or through the material. This action can overcome other forces on the liquid, such as gravity, to promote a desired movement of the liquid. In the thermal conductivity and phase transition heat transfer mechanism, the wicking structure <b>15</b> promotes movement of the condensed liquid back from the cold location <b>7</b> to the hot location <b>13</b>.

0063The wicking structure <b>15</b> may take many forms, such as sintered metal, phosphor, glass or ceramic powder; woven copper; surface grooves, mesh arrangements or small closely spaced wires extending inward from the surfaces of the housing forming the walls of the chamber <b>11</b>; as well as nano-scale wire structures extending inward from the chamber surface(s); and various combinations of these forms. The spacing between elements of the wicking structure <b>15</b> is sufficiently small to cause inter-molecular forces on the liquid form of the working fluid to cause the liquid to flow toward the region where the fluid vaporizes, that is to say, the hot location <b>13</b> in the mechanism <b>1</b>. This wicking or capillary action enables the liquid form of the working fluid to flow back to the hot location regardless of the orientation of (and thus the impact of gravity on fluid in) the heat transfer mechanism <b>1</b>.

0064As noted briefly above, the mechanism <b>1</b> includes an active optical element <b>17</b> that is to be cooled by the thermo-dynamic operation of the combined phase transition heat transfer mechanism. In this case, the active optical element that is to be cooled is a phosphor that emits light when pumped, specifically an opto-luminescent phosphor contained within the chamber <b>11</b>. The opto-luminescent phosphor <b>17</b> is contained within the chamber <b>11</b> formed by the housing <b>3</b> of the thermal conductivity and phase transition heat transfer mechanism <b>1</b>, in such a manner that at least a portion of a surface of the phosphor <b>17</b> is directly contacted by the working fluid through gaps in the wick <b>23</b> formed on the phosphor layer <b>17</b>, at the location <b>13</b> where the fluid evaporates as it absorbs heat. The phosphor may be provided in the chamber in a variety of different ways and other examples will be discussed below with regard to the later drawing figures. In this first example, the phosphor takes the form of a layer at <b>17</b> formed on an inner surface of the chamber <b>11</b>, specifically a layer on the inward facing surface of the optically transmissive member <b>9</b>.

0065The phosphor <b>17</b> will be subject to heating during operation, due to excitation and/or due to heat passing through the housing <b>5</b> into the chamber <b>11</b> from the external source, e.g. if the source is adjacent to the member <b>9</b> and the phosphor <b>17</b>. The working fluid is directly in contact with at least a portion of the opto-luminescent phosphor <b>17</b>.

0066The phosphor within the layer at <b>17</b> is of a type for emitting light when excited by optical energy. Some of the light produced by the excited phosphor passes through one or both of the optically transmissive members <b>9</b>, <b>10</b>. For example, if optical excitation energy is supplied to the phosphor in layer <b>17</b> via the first optically transmissive member <b>9</b>, some phosphor emission may pass back through the optically transmissive member <b>9</b>. However, much of the phosphor emission passes through the chamber <b>11</b> and the optically transmissive member <b>10</b>. As discussed in more detail later, reflective materials may be provided on the walls of the chamber <b>11</b> to reduce loss of light passing through the chamber <b>11</b>. The light for exciting the phosphor may also be applied through the optically transmissive member <b>10</b>, instead of or in addition to excitation energy supplied through the optically transmissive member <b>9</b>.

0067The “phosphor” <b>17</b> here may be any of a variety of optically excited luminescent materials. Terms relating to phosphor are intended to encompass a broad range of materials excited by optical energy of a first or ‘excitation’ band that re-generate light in a different second or ‘emission’ band that is at least somewhat different from the excitation band. Examples of phosphors that may be used in various applications discussed herein include traditional phosphors, such as rare-earth phosphors, as well as semiconductor nanophosphors sometimes referred to as quantum dots or Q-dots, and doped semiconductor nanophosphors. Those skilled in the art will also appreciate that phosphors of similar types and/or of different types, emitting light of different spectral characteristics, may be used in combination.

0068The orientation in the drawing, in which light enters the mechanism <b>1</b> and is emitted from the mechanism <b>1</b> in one or both lateral directions about a somewhat horizontal central axis, is shown only for purposes of illustration. Those skilled in the art will appreciate that the apparatus may be used in any other orientation that is desirable or suitable for any particular application of the mechanism <b>1</b>. Some implementations may utilize additional optically transmissive members, to facilitate receipt or emission of light in additional directions. Although not shown, passive optical processing elements, such as diffusers, reflectors, lens and the like, may be coupled to each optically transmissive member to process light directed into the mechanism <b>1</b> or to process light emitted from the mechanism <b>1</b>.

0069As noted earlier, the wicking structure <b>15</b> may take many forms. The wicking structure may be substantially the same on all of the relevant inner surfaces of the housing <b>5</b>, or there may be somewhat different wicks at different locations within the chamber <b>11</b>. For example, there may be two different types of wicks, one type wick <b>21</b> formed on the thermally conductive section <b>5</b> and possibly the optically transmissive member <b>10</b> and another type wick <b>23</b> formed on the phosphor layer <b>17</b>. For example, the wick <b>23</b> may be transmissive and/or formed of the phosphor material as grooves or wire extensions of the phosphor material. The wick <b>21</b> may be at least somewhat reflective although the portion of the wick on the member <b>10</b> may be transmissive.

0070The example of <figref idref="DRAWINGS">FIG. 1</figref> assumed that the source was outside of the mechanism <b>1</b>, although in that first high-level example, the source was omitted. It may be helpful now to consider an example of a lighting device or system that incorporates a source and a thermal conductivity and phase transition heat transfer mechanism, with reference to <figref idref="DRAWINGS">FIGS. 2A to 3</figref>.

0071<figref idref="DRAWINGS">FIG. 2A</figref> is a back view of an example of a light emitting device or light engine <b>31</b>, <figref idref="DRAWINGS">FIG. 2B</figref> is a cross-sectional view of an example of the light emitting device or light engine <b>31</b> (taken along line B-B of <figref idref="DRAWINGS">FIG. 2A</figref>), and <figref idref="DRAWINGS">FIG. 2C</figref> is an end or plan view of the light emitting device or light engine <b>31</b>. The light emitting device <b>31</b> includes a source <b>33</b> and a thermal conductivity and phase transition heat transfer mechanism <b>35</b> that incorporates an opto-luminescent phosphor within the thermal conductivity and phase transition heat transfer mechanism <b>35</b>. The light emitting device or light engine <b>31</b> also includes a heat sink <b>37</b>.

0072In this example, the source <b>33</b> is outside of the thermal conductivity and phase transition heat transfer mechanism <b>35</b> but coupled to supply optical excitation energy to the mechanism <b>35</b> for optical excitation of the phosphor within the mechanism <b>35</b>. The source may be any type of light emitter configured to supply optical energy in a wavelength range that includes at least a portion of the excitation band of the phosphor included within the mechanism <b>35</b>. Examples of suitable sources include laser diodes and electroluminescent devices. However, most examples of the source <b>33</b> are solid state devices, including a wide range of devices referred to as light emitting diodes (LEDs).

0073As discussed herein, applicable solid state light emitters essentially include any of a wide range light emitting or generating devices formed from organic or inorganic semiconductor materials. Examples of solid state light emitters include semiconductor laser devices and the like. Many common examples of solid state emitters, however, are classified as types of “light emitting diodes” or “LEDs.” This exemplary class of solid state light emitters encompasses any and all types of semiconductor diode devices that are capable of receiving an electrical signal and producing a responsive output of electromagnetic energy. Thus, the term “LED” should be understood to include light emitting diodes of all types, light emitting polymers, organic light emitting diodes (OLEDs), and the like. LEDs may be individually packaged, as in the illustrated example. Of course, LED based devices may be used that include a plurality of LEDs within one package, for example, multi-die LEDs that contain separately controllable red (R), green (G), blue (B) LEDs or the like, within one package. Those skilled in the art will recognize that “LED” terminology does not restrict the source to any particular type of package for the LED type source. Such terms encompass LED devices that may be packaged or non-packaged, chip on board LEDs, surface mount LEDs, and any other configuration of the semiconductor diode device that emits light. Solid state lighting elements may include one or more phosphors and/or nanophosphors, which are integrated into elements of the package to convert at least some radiant energy to a different more desirable wavelength or range of wavelengths.

0074The drawings show a single source, e.g. a single LED, OLED, laser diode, semiconductor nanowire light emitter, or electroluminescent device, at <b>33</b>. However, those skilled in the art will appreciate that many light engine designs for the device <b>31</b> may include a number of similar or different sources, as required to provide sufficient light for a particular application of the light engine <b>31</b>.

0075As in the earlier example of <figref idref="DRAWINGS">FIG. 1</figref>, the mechanism <b>35</b> includes a housing <b>36</b> having a section <b>38</b> that is thermally conductive and two members <b>39</b> and <b>40</b> that are at least partially optically transmissive. Although other shapes or configurations may be used, the example of <figref idref="DRAWINGS">FIGS. 2A-2C</figref> utilizes a cylindrical configuration of the mechanism <b>35</b> similar to that of <figref idref="DRAWINGS">FIG. 1</figref>, but where the cylinder is somewhat flattened or disk shaped so that the axial dimension of the cylinder is smaller than the radial dimension of the cylinder. The optically transmissive members <b>39</b> and <b>40</b> appear flat in cross-section, although they could have other cross-sectional configurations, e.g. convex or concave, if a particular shape would promote light input or light output for a particular application. Larger or additional optically transmissive members and/or members of different lateral shapes may be provided, e.g. to facilitate light input and/or output in a light engine using additional sources. The materials and the thermal and optical properties of the thermally conductive section <b>38</b> and the optically transmissive members <b>39</b>, <b>40</b> forming the housing <b>36</b> can be similar to those discussed above relative to similar elements in the example of <figref idref="DRAWINGS">FIG. 1</figref>.

0076The orientation in <figref idref="DRAWINGS">FIG. 2B</figref>, in which light enters the mechanism <b>35</b> and is emitted from the mechanism <b>35</b> in the left to right direction about a somewhat horizontal central axis, is shown only for purposes of illustration. Those skilled in the art will appreciate that the light engine may be used in any other orientation that is desirable or suitable for any particular application of the mechanism <b>35</b>.

0077The optically transmissive members <b>39</b>, <b>40</b> are attached to the housing section <b>38</b> to form a seal for a vapor tight chamber <b>41</b>. For example, if the optically transmissive members <b>39</b>, <b>40</b> are formed of a glass or ceramic material and the housing section <b>38</b> is formed of a metal, the different elements may be joined by a glass frit process or by application of a suitable epoxy.

0078The heat sink <b>37</b> in this example is formed from two pieces <b>37</b><i>a </i>and <b>37</b><i>b</i>, which together form a tight-fitting cavity enclosing the housing section <b>38</b> of the mechanism <b>35</b>. For example, the pieces <b>37</b><i>a </i>and <b>37</b><i>b </i>form a cylindrical cavity of approximately the same outer size and shape as the thermally conductive section <b>38</b> of the housing <b>36</b>, so that when assembled as shown, the heat sink <b>37</b> provides structural support for the mechanism <b>35</b> and contact of the section <b>38</b> with the pieces <b>37</b><i>a </i>and <b>37</b><i>b </i>provides efficient thermal conductivity for heat transfer from the section <b>38</b> of the housing <b>36</b> to the heat sink <b>37</b>.

0079As shown in <figref idref="DRAWINGS">FIG. 2A</figref>, the piece <b>37</b><i>a </i>of the heat sink <b>37</b> includes a core <b>43</b> and radially extending fins <b>45</b> for radiating heat to the ambient environment, in this case to the surrounding atmosphere. Straight radial fins are shown, for convenience, although other shapes/contours may be used for the fins, e.g. to improve transfer of heat to the ambient atmosphere. The core <b>43</b> of the heat sink <b>37</b> includes an indentation of an appropriate size and shape for securely holding the source <b>33</b>. For example, the outer canister of the source <b>33</b> may serve as the heat slug for the source <b>33</b>, and the canister of the source <b>33</b> may be press fitted into the indentation in the core <b>43</b> of the heat sink <b>37</b>. The mounting of the source <b>33</b> in this way provides both structural support for the source <b>33</b> and efficient thermal conductivity for heat transfer from the source <b>33</b> to the heat sink <b>37</b>.

0080The light output of the source <b>33</b> is coupled to the optically transmissive member <b>39</b> through a passage or aperture <b>47</b> through the core <b>43</b> of the first piece <b>37</b><i>a </i>of the heat sink <b>37</b>. In this way, the source <b>33</b> supplies light, including at least some phosphor excitation energy, into the mechanism <b>35</b>. The optically transmissive member <b>40</b> is coupled to a passage or aperture <b>49</b> through the second piece <b>37</b><i>b </i>of the heat sink <b>37</b>. In this way, light from the source <b>33</b> and/or from excitation of phosphor within the chamber <b>41</b> of the mechanism <b>35</b> emerges through the optically transmissive member <b>40</b> and the passage <b>49</b>. Each passage or aperture <b>47</b>, <b>49</b> may be a physical opening as shown, or each passage or aperture <b>47</b>, <b>49</b> may be formed of or include another optically transmissive element, such as a window, a lens, a holographic diffuser, a color filter or the like. The inner surfaces of the passages <b>47</b>, <b>49</b> may be reflective, e.g. specular or diffusely reflective, to minimize loss of light.

0081Of course, the shape of the depicted elements and the arrangement of parts, in this case for the source, the mechanism and the heat sink, are given here by way of example only. Those skilled in the art will appreciate that other sizes, shapes, arrangements, etc. may be used for particular light engine applications. For example, <figref idref="DRAWINGS">FIG. 2B</figref> shows a relatively straight path from the source <b>33</b> through the two members <b>39</b>, <b>40</b> and out the optical passage <b>49</b>. For some applications, there may be additional members/paths/passages and/or the elements may be arranged to provide a somewhat angled or curved light transmission path.

0082As in the example of <figref idref="DRAWINGS">FIG. 1</figref>, the mechanism or device <b>35</b> also includes an opto-luminescent phosphor contained within the chamber <b>47</b> for emitting light when excited by optical pumping energy from the source <b>33</b>. The phosphor is the active optical element of the mechanism or device <b>35</b>. The particular phosphor of one or more different types is similar to the phosphor discussed above relative to the example of <figref idref="DRAWINGS">FIG. 1</figref>.

0083The arrangement of the phosphor in the mechanism or device <b>35</b> and the separate mounting of the source <b>33</b>, with optical coupling there between, provide a form of “remote” deployment of the phosphor relative to the source <b>33</b> in that the phosphor is outside of the package enclosing the actual semiconductor chip or other light emitter of the source <b>33</b> and thus is apart or remote from the actual light emitter(s). The housing <b>38</b> containing the phosphor may be located at any convenient distance in relation to the light output of the source <b>33</b>. For example, there may be a separation as shown between the light output of the source <b>33</b> and the nearest optically transmissive member <b>39</b>. As another example, to provide efficient coupling of the light from the source <b>33</b> to the mechanism <b>35</b>, the light output of the source <b>33</b> may be adjacent to the optically transmissive member <b>39</b> so that they are in direct contact or so that there is contact through an index of refraction matching material, such as an optical gel or optical adhesive.

0084The phosphor may be provided in the chamber <b>41</b> in a variety of different ways, including some ways outlined above. For example, the phosphor may be provided in the mechanism <b>35</b> as a layer formed on the inner surface of either one or both of the optically transmissive members <b>39</b>, <b>40</b>, similar to the layer <b>17</b> in the example of <figref idref="DRAWINGS">FIG. 1</figref>. Another approach to the phosphor deployment would be to include the phosphor in the working fluid <b>41</b>. The light engine <b>31</b> also includes a wicking structure <b>50</b> mounted within the chamber <b>41</b> to facilitate flow of the condensed liquid of the working fluid from the cold location(s) to the hot location of the mechanism <b>35</b>. The example of <figref idref="DRAWINGS">FIGS. 2A-2D</figref> incorporates the phosphor in the wicking structure, as will be discussed in more detail later, with respect to <figref idref="DRAWINGS">FIG. 2D</figref>.

0085As in the earlier example, a portion of the chamber <b>41</b> within the housing section <b>38</b> will form a cold location <b>53</b> within the chamber <b>41</b>, and the housing section <b>38</b> in that location forms a cold interface for transfer of heat to the heat sink <b>37</b>. In the example of <figref idref="DRAWINGS">FIGS. 2A-2C</figref>, the cold location <b>53</b> is formed around the periphery of the chamber <b>41</b>, such that the outer periphery of the cylindrical section <b>38</b> of the housing serves as the cold interface. The relatively hot location <b>55</b> is in and possibly somewhat around the central region of the chamber between the optically transmissive members <b>39</b>, <b>40</b>. Phosphors in the wicking structure and/or fluid along the inner surfaces of the optically transmissive members <b>39</b>, <b>40</b> would be at the hot location from which the thermal conductivity and phase transition heat transfer mechanism transfers heat.

0086As noted, the exemplary light engine <b>31</b> also includes a working fluid <b>51</b> within the chamber <b>41</b>. The working fluid <b>51</b> is directly in contact with at least a portion of the opto-luminescent phosphor <b>17</b>, in this example, within the wicking structure on one or both of the optically transmissive members <b>39</b>, <b>40</b>. The pressure within the chamber <b>41</b>, typically a pressure somewhat lower than atmospheric pressure, configures the working fluid <b>51</b> to absorb heat during operation of the light engine <b>31</b>, including heat from the phosphor produced by phosphor excitation and/or received from the source <b>33</b>. The working fluid <b>51</b>, in its liquid state, contacts the hot interface at the location <b>55</b> where the mechanism <b>35</b> receives or produces heat. In the example, the working fluid directly contacts at least some surface area(s) of the phosphor at or near the hot location <b>55</b>. When heated at the relatively hot location <b>55</b>, the working fluid <b>51</b> vaporizes. The vapor flows outward to the periphery of the chamber <b>41</b> to the cold location(s) <b>53</b> at the periphery of the chamber <b>51</b> in this example. At the cold location(s) <b>53</b>, heat is transferred from the vapor to the wall of the section <b>38</b> of the housing and from there to the heat sink <b>37</b> for dissipation to ambient air and/or via an external cooling system (not shown). The transfer of heat to the housing section <b>38</b> causes the vapor to condense back to the liquid form, at the relatively cold location(s) <b>53</b>. Through the capillary action of the wicking structure <b>50</b>, the liquid form of the working fluid <b>51</b> flows to the relatively hot location <b>55</b> at the center of the mechanism <b>35</b>. A variety of different fluids may be used as the working fluid, and the pressure is determined based on the fluid type and the amount of heat that the fluid is expected to transfer.

0087The mechanism <b>35</b> within the light engine <b>31</b> in the example thus is configured as a thermal conductivity and phase transition heat transfer mechanism. The thermal conductivity of the housing section <b>38</b> and the phase transition cycle through evaporation and condensation transfer heat from the hot location <b>55</b> to the cold location(s) <b>53</b>. Thermal conductivity at the cold interface allows heat transfer away from the mechanism, e.g. through the heat sink to ambient air.

0088As shown by the discussion of <figref idref="DRAWINGS">FIGS. 2A-2C</figref>, the mechanism <b>35</b> in the light engine <b>31</b> includes a wicking structure <b>50</b> mounted within the chamber <b>41</b> to facilitate the flow of condensed liquid of the working fluid <b>51</b> from the cold location(s) <b>53</b> to the hot location <b>55</b> of the mechanism <b>35</b>. As in the example of <figref idref="DRAWINGS">FIG. 1</figref>, the wicking structure <b>50</b> may take many forms, such as sintered metal, phosphor, glass or ceramic powder; woven copper; surface grooves, mesh arrangements or small closely spaced wires extending inward from the surfaces of the housing forming the walls of the chamber <b>41</b>; as well as nano-scale wire structures extending inward from the chamber surface(s); and various combinations of these forms. The spacing between elements of the wicking structure <b>50</b> is sufficiently small to cause inter-molecular forces on the liquid form of the working fluid <b>51</b> to cause the liquid to flow toward the region where the fluid vaporizes, that is to say, the hot location <b>55</b> in the mechanism <b>35</b>. This wicking or capillary action enables the liquid form of the working fluid to flow back to the hot location regardless of the orientation of (and thus the impact of gravity on fluid in) the heat transfer mechanism <b>35</b>.

0089As discussed more later, particularly with regard to <figref idref="DRAWINGS">FIGS. 2D</figref>, <b>2</b>E and <b>4</b>, the mechanism <b>35</b> in our example uses wicks for the structure <b>50</b> that utilize nanowires. Nanowires are wire-like structures having nano-scale cross-sectional dimensions. Although the cross-section of a nanowire may not be circular, it is often easiest to consider the lateral dimension of the nanowire to be a diameter. A nanowire therefore may have an outer diameter measured in nanometers, e.g. in a range of approximately 1-500 nanometers. Hence, “nanowire” is meant to refer to any continuous wire or filament of indefinite length having an average effective diameter of nanometer (nm) dimensions. The “nanowire” term is therefore intended to refer to nanostructures of indefinite length, which may have a generally circular cross-sectional configuration or a non-circular cross-section (e.g. nanobelts having a generally rectangular cross-section).

0090Also as noted above, the mechanism <b>35</b> includes an active optical element, in this case, a phosphor within the chamber <b>41</b> that is to be cooled by the thermo-dynamic operation of the combined phase transition heat transfer mechanism. At least a portion of a surface of the phosphor is directly contacted by the working fluid <b>51</b> at the location <b>55</b> where the fluid evaporates as it absorbs heat. The phosphor may be provided in the chamber in a variety of different ways, for example, as a layer like that in <figref idref="DRAWINGS">FIG. 1</figref> or carried by the working fluid <b>51</b>. However, for purposes of further discussion of the example of <figref idref="DRAWINGS">FIGS. 2A-2E</figref>, we will consider an arrangement in which the phosphor forms or is carried by material forming a nanowire structure serving as a portion of the wicking structure <b>50</b> of the mechanism <b>35</b>. Other portions of the wicking structure <b>50</b> may have other structures or characteristics, although the specific example below will concentrate on an arrangement in which some or all of the other portions of the wicking structure <b>50</b> are at least somewhat reflective.

0091<figref idref="DRAWINGS">FIG. 2B</figref> shows partially enlarged views of sections E-E and D-D of the chamber wall and associated wicking structures at two different exemplary locations. The view D-D corresponds to a location on one of the optically transmissive members, for example, of member <b>40</b>; whereas the view E-E corresponds to a location on the thermally conductive section <b>38</b> of the housing of the mechanism <b>35</b>. <figref idref="DRAWINGS">FIG. 2D</figref> is a further enlarged view corresponding to D-D in <figref idref="DRAWINGS">FIG. 2B</figref>, and <figref idref="DRAWINGS">FIG. 2E</figref> is a further enlarged view corresponding to E-E in <figref idref="DRAWINGS">FIG. 2B</figref>.

0092<figref idref="DRAWINGS">FIGS. 2D and 2E</figref> show two specific examples of arrangements that may be used as portions <b>50</b><i>a </i>(<figref idref="DRAWINGS">FIG. 2D) and 50</figref><i>b </i>(<figref idref="DRAWINGS">FIG. 2E</figref>) of the wicking structure <b>50</b> in the light engine <b>31</b> of <figref idref="DRAWINGS">FIGS. 2A-2C</figref>. The example of <figref idref="DRAWINGS">FIG. 2E</figref> uses a wicking arrangement <b>50</b><i>a </i>formed of nanowires <b>56</b> on a surface of one of the optically transmissive members. The nanowire wicking arrangement could be on either one or both of the optically transmissive members <b>39</b>, <b>40</b>, although for convenience, the enlarged view in <figref idref="DRAWINGS">FIG. 2D</figref> shows the nanowire wicking structure arrangement <b>50</b><i>a </i>formed on the inner surface of the optically transmissive member <b>40</b>. The nanowires <b>56</b> of the wicking structure <b>50</b><i>a </i>are formed of or include an optically luminescent material, of a type discussed earlier relative to <figref idref="DRAWINGS">FIG. 1</figref>. The phosphor or a medium bearing the phosphor may be grown as nanowires <b>56</b> extending inward into the interior of the chamber <b>41</b> from the inner surface of the either one or both of the optically transmissive members <b>39</b>, <b>40</b>. By way of an example, particles of suitable phosphor(s) may be dispersed in a polymer matrix, and the phosphor-polymer matrix is grown in the form of nanowires. Examples of suitable polymers include epoxies and silicon. A barrier layer of a few nanometers up to around a micron may be provided on the surface of the phosphor nanowires <b>56</b>, so long at the barrier layer does not substantially impede flow of light to or from the phosphor or flow of heat from the excited phosphor to the fluid.

0093The phosphor converts some of the optical energy within the chamber <b>41</b> from energy in one wavelength range (the excitation band of the phosphor) to another somewhat different wavelength range. There may or may not be some overlap of the excitation and emission spectra of the phosphor. In the light engine <b>31</b> of <figref idref="DRAWINGS">FIGS. 2A-2C</figref>, the phosphor may convert some energy from the source <b>33</b> from a less desirable wavelength range (e.g. near or outside the visible spectrum) to a more desirable wavelength range (e.g. to fill-in a gap in the spectrum of the output of light engine <b>31</b> and/or to improve the quality of the light output). For example, the phosphor in the nanowires <b>56</b> receives light emitted by the source through one optically transmissive member <b>39</b>, recycles such light and retransmits it within the chamber <b>41</b> for passage through the optically transmissive member <b>39</b>.

0094The mechanism <b>35</b> of the light engine <b>31</b> is configured with the wicking arrangement <b>50</b><i>a </i>formed of nanowires <b>56</b> that contain phosphor in regions where the phosphor is most likely to receive optical pumping energy from the source <b>33</b> and re-emit converted light for output as part of the light output of the light engine <b>31</b> through the optical aperture <b>49</b>, that is to say on one or both of the optically transmissive members <b>39</b>, <b>40</b>. The wicking arrangement <b>50</b><i>b </i>could similarly include phosphor nanowires. However, in the example, instead of a phosphor wicking structure as in <figref idref="DRAWINGS">FIG. 2D</figref>, the example of <figref idref="DRAWINGS">FIG. 2E</figref> uses a metal nanowire wicking structure <b>50</b><i>b</i>. In the example of <figref idref="DRAWINGS">FIG. 2E</figref>, metallic nanowires <b>57</b> of sufficient size and closeness to function as the wicking structure are grown so as to extend inward from the inner surface of the section <b>38</b> of the housing. In addition to supporting the capillary wicking function, the nanowires <b>57</b> may also be reflective to reflect light within the chamber <b>41</b> back to the area of optically transmissive member <b>40</b>, so as to improve re-circulation of light within the chamber <b>41</b> and thereby improve overall optical performance of the light engine <b>31</b>.

0095Although referred to as a phosphor, each nanowire may include one or more phosphors of different types where the mix of phosphors is chosen to promote a particular application of the apparatus <b>1</b>. Another multi-phosphor approach might use a phosphor of one type in nanowires in one region of the chamber and a phosphor of another type in a different region of the chamber.

0096In both the examples of <figref idref="DRAWINGS">FIGS. 2D and 2E</figref>, the working fluid <b>51</b> may also be or include a phosphor or the like. If phosphor particles are contained in the fluid <b>51</b>, the particle surfaces may be exposed to the fluid or the particles may be encapsulated in a barrier layer of a few nanometers up to around a micron, so long at the barrier layer does not substantially impede flow of light to or from the phosphor or flow of heat from the excited phosphor to the fluid medium. The phosphor in the working fluid <b>51</b> may enhance certain aspects of the light engine performance in a manner similar to that discussed above relative to the phosphor of the nanowires <b>56</b> in the example of <figref idref="DRAWINGS">FIG. 2D</figref>.

0097The examples of <figref idref="DRAWINGS">FIGS. 2D and 2E</figref> relate to different nanowire arrangements for one or more portions of the wicking structure. In both cases, the size and spacing of the nanowires would be such as to provide a capillary flow of the liquid form of the working fluid. The working fluid <b>51</b> would directly contact the outer surface(s) of the respective nanowires and thus at least some phosphor material within the nanowires <b>57</b> and/or the working fluid <b>51</b> would contain phosphor itself.

0098Thermal conductivity and phase transition heat transfer mechanisms that incorporate phosphor materials to be cooled by operation of the mechanisms under discussion herein can be used in a variety of different types of light emitting devices, apparatuses and systems. The light engine <b>31</b>, for example, may be incorporated into various designs for light bulb type lamps; floor, desks or table lamps; light fixtures; displays; as well a lamps and fixtures for use in vehicles.

0099To help illustrate, consider the simplified example of <figref idref="DRAWINGS">FIG. 3</figref>, which is a cross-sectional view of an example of a light fixture <b>61</b> incorporating a light engine <b>31</b> like that shown in <figref idref="DRAWINGS">FIG. 2B</figref>. The fixture <b>61</b> thus includes the light engine <b>31</b> for producing the light intended for output from the fixture <b>61</b> together with one or more passive optical processing elements, such as diffusers, reflectors, lens and the like, optically coupled to the output aperture or passage <b>49</b> of the light engine <b>31</b>.

0100In the example, the additional passive optical processing elements coupled to the output aperture or passage <b>49</b> include a reflective coating or disk <b>63</b> on an output face of the light engine <b>31</b> and surrounding the optical output aperture <b>49</b> (through the second piece <b>37</b><i>b </i>of the heat sink <b>37</b> in <figref idref="DRAWINGS">FIGS. 2B and 2C</figref>). The passive optical processing elements of the fixture <b>61</b> also include a truncated conically shaped reflector <b>65</b> and a diffuser <b>67</b>. The proximal end of the truncated cone of the reflector <b>65</b> connects to or matches with the outer periphery of the reflective coating or disk <b>63</b>. The diffuser <b>67</b> is located at or near the distal end opening of the reflector <b>67</b>.

0101The reflective surfaces of the reflective disk <b>63</b> and the reflector <b>65</b> may be specular, quasi-specular or diffusely reflective. Although shown as separate components, the reflective disk <b>63</b> and reflector <b>65</b> may be formed as a single unified reflective element. Also, the elements <b>63</b>, <b>65</b> are shown as relatively flat cross-sectional shapes, although one or both may be curved or form angles. For example, the disk <b>63</b> and reflector <b>65</b> may be configured to form a parabolic reflector, to provide a more beam-shaped output of the fixture <b>61</b>.

0102The surface of the diffuser <b>67</b> may be a translucent white material which passes and diffuse some light and tends to diffusely reflect some light back within the optical chamber formed by the reflective disk <b>63</b>, the reflector <b>65</b> and the diffuser <b>67</b>. If the reflective disk <b>63</b> and the reflector <b>65</b> are diffusely reflective, the chamber may perform at least some optical integration of light from the source and the phosphor before emission of light via transmission through the diffuser <b>67</b>.

0103The disclosed fixture <b>61</b> may use a variety of different structures or arrangements for the disk <b>63</b>, reflector <b>65</b> and diffuser <b>67</b>. For efficiency, the reflective surfaces of the disk <b>63</b> and of the reflector <b>67</b> should be highly reflective. In the example, the light engine <b>31</b> is arranged in the fixture <b>61</b> so as to emit most of the light energy toward the diffuser <b>67</b>. To increase the optical integration and reduce possible pixilation or striation, the light engine <b>31</b> is arranged in the fixture <b>61</b> so as to emit light toward a reflective surface in such a manner that direct emissions form the aperture <b>49</b> are not directed to a transmissive output portion of the fixture (not directly toward the diffuser <b>67</b> in our example).

0104The orientation in the drawing, in which light from the engine <b>31</b> is emitted downward, is shown only for purposes of illustration. Those skilled in the art will appreciate that the light fixture <b>61</b> may be used in any other orientation that is desirable or suitable for any particular application.

0105Fixtures of the type shown in <figref idref="DRAWINGS">FIG. 3</figref> may combine the source, the reflector/diffuser elements and the thermal conductivity and phase transition heat transfer mechanism <b>35</b> that incorporates an opto-luminescent phosphor in a variety of other configurations. The remote phosphor may be provided in or about the optic formed by the source and the reflector/diffuser elements in any of a number of different ways or locations. For example, in another configuration, the thermal conductivity and phase transition heat transfer mechanism might have a reflective inner walled thermally conductive section with the phosphor deployed on the thermally conductive member and otherwise shaped like the combined reflector formed by <b>63</b> and <b>65</b> in the example of <figref idref="DRAWINGS">FIG. 3</figref>. Light reflected within the chamber would pump the phosphor and be reflected for passage through the diffuser <b>67</b>.

0106As discussed, <figref idref="DRAWINGS">FIG. 3</figref> represents an example of a light fixture. Although not shown, a lighting system that uses the engine <b>31</b> would include the engine and other elements forming the fixture or the like, in combination with appropriate electronics to drive the particular source <b>33</b>. For example, if the source <b>33</b> includes one or more solid state light emitters, such as one or more LEDs, then the electronics would include a power supply for deriving DC power from the main source (DC battery or AC main lines) and driver circuitry for converting the derived DC to a form appropriate to drive the particular solid state emitter(s) at the output level appropriate for the intended lighting application. The power supply and driver circuitry are omitted from this and later examples for convenience, although those skilled in lighting will be quite familiar with such system components.

0107As noted earlier, the wicking structure may take various forms. The examples of <figref idref="DRAWINGS">FIGS. 2A to 3</figref> utilized nanowire wicks. The use of nanowires in the wicking structure, particularly at the hot and cold locations, improves heat transfer.

0108In general, smaller more numerous heat transfer elements at these locations present increased surface area for heat transfer to/from the working fluid and therefore represent decreased thermal resistance. <figref idref="DRAWINGS">FIG. 4</figref> is a comparative diagram useful in explaining how reducing the size and increasing the number of thermal elements per unit area of the housing wall increases total surface area for heat transfer and reduces the thermal resistance, both of which help to improve the rate of thermal transfer to/from the working fluid contacting the thermal transfer elements, in this case contacting the nanowires. It is believed that this comparison helps demonstrate and explain advantages of using nanowires or similarly sized elements in the wicking structure of the combined phase transition heat transfer mechanism of an optical/electrical transducer apparatus.

0109For discussion purposes, the square under each identifier (A), (B) and (C) represents a 2 mm×2 mm section of an inner surface of the vapor chamber of a thermal conductivity and phase transition heat transfer mechanism. However, the different examples (A), (B) and (C) have different sizes and numbers of heat transfer elements extending into the interior of the chamber. In the illustrated views, the heat transfer elements appear as circles, representing the end view (from inside the vapor chamber) of cylindrical heat transfer elements. Cylindrical shapes are used here for ease of modeling, although as noted earlier, other shapes may be used. For purposes of this comparison, we will assume that the heat transfer elements are all formed of same material in each and every one of the three examples of <figref idref="DRAWINGS">FIG. 4</figref>.

0110The first example (A) has four pins of radius 0.25 mm (diameter of 0.5 mm). The length of the pins L need not be specified for comparison purposes. The number 4 in the formulae for the example is the number of pins. The volume of each pin is 2π times the radius-squared times the length (L) of the pins. As shown, the total volume of the material of the four pins is 0.25²*2π*L*4, which equals 0.78L. For purposes of calculation of the surface area, we will use the outer cylindrical surface only (without including the end surfaces) to somewhat simplify the calculations for the comparison. With that approach, the surface area of a cylindrical pin is the diameter times π times the length. Hence, the total cylindrical outer surface area presented by the four pins at (A) would be 0.5*π*L*4, which equals 6.2L. The thermal resistance of each pin equals the pin radius times the thermal resistance R of the material from which the pins are formed. In the example (A) in which the radius of the pins is 0.25 mm, the thermal resistance of each pin is 0.25*R.

0111The second example (B) has sixteen (16) pins of radius 0.125 mm (diameter of 0.250 mm) of the same length L as in the previous example. As shown, the total volume of the material of the sixteen pins is 0.125²*2π*L*16, which again equals 0.78L. Again, using only the cylindrical surface area for purposes of comparison (without including the end surfaces), the total cylindrical outer surface area presented by the sixteen pins at (B) would be 0.25*π*L*16, which equals 12.5L. This decrease in size and increase in number of pins results in approximately doubling the surface area for heat transfer in comparison to example (A). The thermal resistance of each pin in example (B), equals 0.125*R, which is half the thermal resistance of example (A).

0112The use of nanowires in the wicking structure, particularly in the vicinity of the hot location and/or the cold location <b>7</b>, increases both the surface area for heat transfer and reduces the thermal resistance of each heat transfer element. Increased surface area and decreased thermal resistance both contribute to improved heat transfer. Example (C) in <figref idref="DRAWINGS">FIG. 4</figref> represents a nanowire configuration in which the 2 mm×2 mm area of the chamber wall has 9.9×10⁹nanowires, where the radius of each nanowire is 5×10⁻⁶mm (5 nanometers) or the diameter of each nanowire is 10×10⁻⁶mm (10 nanometers).

0113As shown at (C), the total volume of the material of the nanowires is (5×10⁻⁶)²*2π*L*(9.9×10⁹), which again equals 0.78L. Again, using only the cylindrical surface area for purposes of comparison (without including the end surfaces), the total cylindrical outer surface area presented by the nanowires at (C) would be 10×10⁻⁶*π*L*9.9×10⁹, which equals (3.1×10⁵)L, which is approximately 50,000 times more surface area for heat transfer than in first example (A). The thermal resistance of each nanowire in example (C), equals (5×10⁻⁶)*R, which is approximately 50,000 times lower than the thermal resistance of example (A).

0114Hence, the use of nanowires in the wicking structure at various points in the exemplary light emitters discussed herein improves thermal transfer capabilities. At a hot location or interface, use of nanowires improves transfer of heat to the working fluid. At a cold location, use of nanowires improves transfer of heat from the working fluid to the cold interface, e.g. for transfer through the interface to a heat sink, active cooling element or ambient air.

0115The use of the nanowires also helps with the wicking action. As noted, inter-molecular forces between a liquid and the surface(s) of the wicking material around the liquid produce capillary action to move of the liquid form of the working fluid along or through the material. Increasing the surface area helps to increase the inter-molecular forces on the liquid form of the working fluid. Hence, use of nanowires as the wicking structure, with the increased surface area as shown above, also increases the strength of the capillary action of the wicking structure on the liquid form of the working fluid.

0116As noted earlier, a variety of different fluids may be used as the working fluid. Different fluids are used in various light emitting devices or engines to support the heat transfer function. In some examples noted above, the working fluid also serves as a carrier for phosphor. In several examples discussed later, the working fluid may also serve as a conductor (with or without include phosphor). For a working fluid that would carry semiconductor nano-phosphor as the phosphor, examples of suitable fluids include acetone, methanol, ethanol and toluene. If the nano-phosphor is well encapsulated, water may be on option. Toluene may be a preferred choice for many phosphors, however, for cooler internal working temperatures, ethanol me be preferred. For a working fluid that would carry rare-earth-phosphor, examples of suitable fluids include acetone, methanol ethanol and toluene, although here water may be a preferred choice. For a working fluid that is also electrically conductive, examples of suitable fluids include salt water, ammonia and fluids from the class of transparent ionic liquids.

0117The example of <figref idref="DRAWINGS">FIG. 3</figref> related to use of a thermal conductivity and phase transition heat transfer mechanisms that incorporate phosphor materials to be cooled by operation of the mechanism in a light fixture. As noted, such mechanisms may be utilized in other devices for emitting light, including in lamps. It may be helpful to consider an example of a lamp product that conforms to a fairly common form factor, specifically, the form factor of an A-lamp.

0118<figref idref="DRAWINGS">FIG. 5</figref> illustrates an example of a solid state lamp <b>130</b>. The exemplary lamp <b>130</b> may be utilized in a variety of lighting applications analogous to applications for common incandescent lamps and/or compact fluorescent lamps. The lamp <b>130</b> includes solid state light emitters <b>132</b> for producing lamp output light of a desired characteristic, from the emitter outputs and from luminescent phosphor emissions driven by the emitter outputs as discussed more fully below. The solid state emitters as well as the other components within the bulb <b>131</b> are visible in the cross-sectional view of <figref idref="DRAWINGS">FIG. 6</figref>.

0119At a high level, a lamp <b>130</b> includes solid state light emitters <b>132</b>, a bulb <b>131</b> and a pedestal <b>133</b>. The bulb <b>131</b> may be either transparent or diffusely transmissive. The pedestal <b>133</b> extends into an interior of the bulb <b>131</b> and supports the solid state light emitters <b>132</b>. In the example, the pedestal is attached to the hot interface of a thermal conductivity and phase transition heat transfer mechanism in the form of a shaped tubular heat pipe <b>138</b>, although the pedestal may be formed as an integral portion of the heat pipe <b>138</b>.

0120The pedestal <b>133</b> may be cylindrical in cross-section with one or more emitters <b>132</b> mounted on the distal end face of the cylinder and others of the emitters mounted around the cylindrical longitudinal surface. Alternatively, the pedestal <b>133</b> may have a polygonal cross-section with several outward facing surfaces. Again, one or more emitters <b>132</b> would be mounted on the distal end face of the pedestal <b>133</b>; and one or more of the emitters <b>132</b> would be mounted on each of the outward facing surfaces of the polygonal shaped pedestal. The drawing illustration in represents a pedestal with a somewhat triangular cross section have three major surfaces facing laterally outward in three different orientations, each for supporting one or more emitters <b>132</b>. The orientations of the solid state light emitters <b>132</b> from the end face and the lateral surface(s) of the pedestal <b>133</b> produce emissions through the bulb <b>131</b> that approximate light source emissions from a filament of an incandescent lamp.

0121The orientation in the drawings, in which the bulb <b>131</b> is at the top and much of the light emissions form the lamp are horizontal and upward about a vertical central axis of the lamp <b>130</b>, is shown only for purposes of illustration. Those skilled in the art will appreciate that the lamp may be used in any other orientation that is desirable or suitable for any particular application of the transducer apparatus.

0122In this example, a thermal conductivity and phase transition heat transfer mechanism <b>134</b> that incorporates a phosphor to be cooled by operation of the mechanism is positioned radially and longitudinally around the solid state light emitters <b>132</b> supported on the pedestal and between an inner surface of the bulb <b>131</b> and the solid state light emitters <b>132</b>. The mechanism <b>134</b> is formed of a thermally conductive section and an optically transmissive member and contains phosphors in a manner similar to the examples of <figref idref="DRAWINGS">FIGS. 1-4</figref> (and as will be described in more detail, later, with regard to <figref idref="DRAWINGS">FIGS. 7 and 8</figref>). In contrast, the housing of the heat pipe <b>138</b> is entirely formed of thermally conductive material and is not optically transmissive; and the heat pipe <b>138</b> need not include any phosphor.

0123The lamp <b>130</b> also includes a heat sink <b>136</b>. A straight section <b>138</b><i>a </i>of the heat pipe <b>138</b> supports the pedestal <b>133</b> with the light emitters <b>134</b> and provides the hot interface for the light emitters. A spiral straight section <b>138</b><i>a </i>of the heat pipe <b>138</b> is mechanically connected to an interior wall of the heat sink <b>136</b>, to provide structural support and to provide the cold interface for transfer of heat out of the heat pipe to the heat sink <b>136</b>.

0124The heat sink <b>136</b> has a modular-coupling for attachment of one of a number of different lighting industry standard lamp bases <b>135</b>. The heat sink <b>136</b> also has a second modular-coupling for attachment of one of a number of different types of bulbs <b>131</b> and a third modular-coupling for attachment of one of a number of different types thermal conductivity and phase transition heat transfer mechanism <b>134</b>. Although they may differ somewhat as to shape, e.g. in the region around the emitters <b>132</b> on the pedestal <b>133</b>, the different types of the mechanism <b>134</b> typically will have different mixtures of one or more phosphors with the mechanisms, so that different instances of the lamp <b>130</b> will produce white light output of somewhat different spectral characteristics, e.g. different color temperatures and/or different levels of white light color quality. The base, heat sink and bulb also enclose circuitry on a circuit board (not shown) inside the coil <b>138</b><i>b </i>of the heat pipe <b>138</b>, to receive electricity from the lamp base <b>135</b>, for driving the solid state emitters <b>132</b> of the source to emit the light.

0125The solid state light emitters <b>132</b> in the exemplary lamp may be driven/controlled by a variety of different types of circuits. Depending on the type of solid state emitters selected for use in a particular lamp product design, the solid state emitters may be driven by AC current, typically rectified; or the solid state emitters may be driven by a DC current after rectification and regulation. The degree of control may be relatively simple, e.g. ON/OFF in response to a switch, or the circuitry may utilize a programmable digital controller, to offer a range of sophisticated options. Intermediate levels of sophistication of the circuitry and attendant control are also possible.

0126The modular couplings facilitate use of certain common components that form a light engine together with different bulbs <b>131</b>, bases <b>135</b> and/or inner mechanisms <b>134</b> with different phosphors for different lamp configurations. The common components forming the engine may include the pedestal <b>133</b>, the emitters <b>132</b>, the heat pipe <b>138</b> and the heat sink <b>136</b>.

0127In the example, the pedestal <b>133</b> on the straight section <b>138</b><i>a </i>of the heat pipe <b>138</b> extends from the heat sink <b>136</b> along the longitudinal axis of the light engine/lamp into a region to be surrounded by the bulb <b>131</b> when attached to the heat sink member at the first modular-coupling. The heat pipe <b>138</b> and the pedestal <b>133</b> provide heat conductivity to the heat sink <b>136</b> as well as support from the heat sink <b>136</b>, for the light emitters <b>132</b>. The portion of the straight section <b>138</b><i>a </i>of the heat pipe <b>138</b> serves as the hot interface to receive heat from operation of the light emitters <b>132</b> via the thermally conductive material forming the pedestal <b>133</b>. The coil section <b>138</b><i>b </i>of the heat pipe <b>138</b> as the is mechanically and thermally coupled to the interior wall of a core of the heat sink <b>136</b> and serves as the cold interface for transfer of heat out of the pipe <b>138</b> to the heat sink <b>136</b>. The heat sink <b>136</b> in turn dissipates the heat, e.g. to ambient atmosphere. Although not shown, air passages may also be provided through the coupling of the heat sink to the bulb and or to/from the interior of the inner optical processing member to allow flow of air around the emitters and venting thereof to the exterior of the lamp <b>130</b>.

0128In the example of <figref idref="DRAWINGS">FIGS. 5 and 6</figref>, the heat sink fins <b>136</b><i>a </i>have an outward curved or slightly angled profile at their outer edge. The heat sink <b>136</b> may also includes flares on the fins extending in a somewhat circumferential manner. If provided, the flares may be located between the proximal and distal ends of the fins <b>136</b><i>a </i>or at the distal ends of the fins <b>136</b><i>a</i>. The flares may follow the outer curvature of the fins <b>136</b><i>a </i>or the flares may be curved inward (as opposed to the outer curve at the perimeter of the fins). Longitudinally, the length of the fins <b>136</b><i>a </i>extends from the bulb <b>131</b> down to the base <b>135</b>. Various fin and flare designs may be used. For a given lamp design, the fins and flare will generally be configured to provide good heat dissipation to the ambient atmosphere but may also be configured to allow some light passing outward through the bulb <b>131</b> to pass through the gaps between the fins and thereby provide a some output for the lamp <b>130</b> downward in the illustrated orientation.

0129The solid state lamps in the examples produce light that is at least substantially white. In some examples, the solid state emitters <b>132</b> produce light that is at least substantially white but at a first color temperature (<figref idref="DRAWINGS">FIG. 13B</figref>), and phosphor(s) in the mechanism <b>134</b> converts some of that light so that the lamp output is at least substantially white but at a second color temperature. In other examples, the solid state emitters <b>132</b> produce light that would not normally be considered white but is particularly effective at pumping phosphors in the mechanism <b>134</b> so that the overall lamp output is at least substantially white. In these various examples, light is at least substantially white if human observers would typically perceive the light in question as white light. The types of phosphor or phosphor used are the same as discussed above, e.g. with respect to the example of <figref idref="DRAWINGS">FIG. 1</figref>.

0130The solid state light emitters <b>132</b> are semiconductor based structures for emitting light, in some examples for emitting substantially white light and in other examples for emitting light of color in a range to pump phosphors. In the example, the light emitters <b>132</b> comprise light emitting diode (LED) devices, although other semiconductor devices might be used as the source.

0131As noted, the thermal conductivity and phase transition heat transfer mechanism <b>134</b> that incorporates the phosphor may be constructed in a manner similar to the examples of <figref idref="DRAWINGS">FIGS. 1-4</figref>, although as shown in <figref idref="DRAWINGS">FIGS. 6 and 7</figref>, the mechanism is shaped to fit around and be somewhat separated from the pedestal <b>133</b> and the LED type solid state light emitters <b>132</b>. It may be helpful to discuss the example of the mechanism <b>134</b> in somewhat more detail with reference to the enlarged views of <figref idref="DRAWINGS">FIGS. 7 and 8</figref>. <figref idref="DRAWINGS">FIG. 7</figref> shows the portion of lamp cross-section encompassed by the oval <b>7</b> in <figref idref="DRAWINGS">FIG. 6</figref>, including the thermal conductivity and phase transition heat transfer mechanism <b>134</b> and the coupling thereof to the heat sink <b>136</b>; whereas <figref idref="DRAWINGS">FIG. 8</figref> shows portions of the walls and wicks for the thermally conductive housing section and the optically transmissive members encompassed by the circle <b>8</b> in <figref idref="DRAWINGS">FIG. 7</figref>.

0132As in the earlier examples, the mechanism <b>134</b> includes a housing <b>146</b> having a section <b>148</b> that is thermally conductive and two members <b>149</b> and <b>150</b> that are at least partially optically transmissive. Although other shapes or configurations may be used, the example of <figref idref="DRAWINGS">FIGS. 7 and 8</figref> utilizes a cylindrical configuration with a dome at the distal end, for each of the optically transmissive members <b>149</b> and <b>150</b>. The optically transmissive member <b>150</b> is somewhat smaller than the optically transmissive member <b>149</b>, and the members <b>149</b>, <b>150</b> are attached to the housing section <b>148</b> so as to be concentric. In this way, a space is formed between the optically transmissive members <b>149</b> and <b>150</b>. The thermally conductive section <b>148</b> of the housing <b>148</b> is cylindrical in this example, having two concentric cylindrical walls <b>148</b><i>a</i>, <b>148</b><i>b </i>joined by a flat section <b>148</b><i>c </i>at the proximal end of the section <b>148</b>. The walls <b>148</b><i>a </i>and <b>148</b><i>b </i>and the flat section may be formed as a single integral member or manufactured separately and bonded together by welding, soldering or the like. The cylindrical wall <b>148</b><i>b </i>is somewhat smaller than the cylindrical wall <b>148</b><i>c</i>, and the attachment through the flat section <b>148</b><i>c </i>positions the two walls so as to be concentric. In this way, the two concentric cylindrical walls <b>148</b><i>a</i>, <b>148</b><i>b </i>are separated by a space similar to the space between the optically transmissive members <b>149</b> and <b>150</b>. The inner area at the proximal end of the section <b>148</b> provides an opening for coupling to the heat sink <b>136</b>. The optically transmissive members <b>149</b>, <b>150</b> are attached to the housing section <b>148</b> to form a seal for a vapor tight chamber <b>151</b>. For example, if the optically transmissive members <b>149</b>, <b>150</b> are formed of a glass or ceramic material and the housing section <b>16</b> is formed of a metal, the different elements may be joined by a glass frit process or by application of a suitable epoxy. The materials and the thermal and optical properties of the housing section <b>148</b> and the members <b>149</b>, <b>150</b> forming the housing <b>146</b> can be similar to those discussed above relative to similar elements in the example of <figref idref="DRAWINGS">FIG. 1</figref>.

0133The heat sink <b>147</b> in this example is made of a highly thermally conductive material, typically a metal such as aluminum or copper, although other thermally conductive material materials, such as thermally conductive plastics and ceramics. The distal end (upper in <figref idref="DRAWINGS">FIG. 6</figref>) of the heat sink <b>136</b> is configured to provide a central axial passage <b>152</b> for the straight section <b>138</b><i>a </i>for mechanical connection and thermal coupling of the heat pipe <b>138</b> to the heat sink <b>138</b>. The passage <b>152</b> may be only slightly larger in diameter than the outer diameter of the straight section <b>138</b><i>a </i>to provide a tight fit, or the straight section <b>138</b><i>a </i>may be bonded into the passage <b>152</b>, e.g. welding, soldering, epoxy or the like.

0134The distal end of the heat sink <b>136</b> is configured to provide a modular coupling for the thermal conductivity and phase transition heat transfer mechanism <b>134</b>, which contains the phosphor. Although other coupling arrangements may be used, in the example, the coupling takes the form of a circular groove or indentation <b>154</b>. The distal portion of the housing section <b>148</b> is mounted in the matching circular groove <b>154</b> formed in the distal end of the heat sink <b>136</b>. Although it may be somewhat deeper than necessary, the lateral dimensions of the groove <b>154</b> provide a width between the inner and outer walls of the groove that is only slightly larger than the width of the housing section (from outside surface of wall <b>148</b><i>a </i>to opposite outside surface of wall <b>148</b><i>b</i>). The housing section <b>148</b> of the mechanism <b>134</b> may be press fitted into the groove <b>154</b> and/or bonded to the heat sink, for example, by welding, soldering, epoxy or the like.

0135The mounting of the housing section <b>148</b> in the groove <b>154</b> provides structural support for the mechanism <b>134</b> and provides good thermal conductivity for the flow of heat from the housing section <b>148</b> to the surrounding portion of the heat sink. This thermal connection provides a cold interface for the thermal conductivity and phase transition heat transfer mechanism <b>134</b>.

0136As in the example of <figref idref="DRAWINGS">FIG. 1</figref>, the mechanism or device <b>134</b> also includes an opto-luminescent phosphor contained within the chamber <b>157</b> for emitting light when excited by optical pumping energy from the source <b>143</b>. The phosphor is the active optical element of the mechanism or device <b>134</b>; although the lamp includes the source (another active optical element) formed by the emitters <b>132</b> which are external with respect to the mechanism and the phosphor therein, as well as a passive optical element in the form of the bulb <b>131</b>. The particular phosphor of one or more different types is similar to the phosphor discussed above relative to <figref idref="DRAWINGS">FIG. 1</figref>.

0137The arrangement of the phosphor in the mechanism or device <b>134</b> separate from the emitter <b>132</b>, with optical coupling there between, provides a form of “remote” deployment of the phosphor relative to the source formed by the emitters <b>132</b> in that the phosphor is outside of the package enclosing the actual semiconductor chip of each solid state light emitter <b>132</b> and thus is apart or remote from the actual light emitter(s). The housing <b>148</b> containing the phosphor may be located at any convenient distance in relation to the light output of the source <b>143</b>. For example, there may be a larger or smaller separation than that shown between the emitters <b>132</b> and the nearest optically transmissive member <b>150</b>.

0138Again, the phosphor may be provided in the chamber <b>151</b> in a variety of different ways, including some ways outlined above. For example, the phosphor may be provided in the mechanism <b>134</b> as a layer formed on the inner surface of either one or both of the optically transmissive members <b>149</b>, <b>150</b>, similar to the layer <b>17</b> in the example of <figref idref="DRAWINGS">FIG. 1</figref>. Another approach to the phosphor deployment would be to include the phosphor in the working fluid <b>161</b>. The mechanism <b>134</b> in the example also includes a wicking structure <b>160</b> mounted within the chamber <b>151</b> to facilitate flow of the condensed liquid of the working fluid from the cold location(s) to the hot location of the mechanism <b>134</b>. The example of <figref idref="DRAWINGS">FIG. 8</figref> incorporates the phosphor in the wicking structure, in a manger similar to the arrangement described above with respect to <figref idref="DRAWINGS">FIG. 2D</figref>.

0139As in the earlier example, a portion of the chamber <b>151</b> within the housing section <b>148</b> will form a cold location <b>163</b> within the chamber <b>151</b>, and the housing section <b>148</b> in that location forms a cold interface for transfer of heat to the heat sink <b>136</b>. In the example of <figref idref="DRAWINGS">FIGS. 7 and 8</figref>, the cold location <b>163</b> is formed around the portion of the chamber <b>151</b> at the proximal end of the mechanism <b>134</b>, that is to say, in the portion of the chamber inside the proximal end of the housing section <b>148</b>, such that the part of the housing section <b>148</b> connected to the heat sink <b>136</b> serves as the cold interface. The relatively hot location <b>165</b> is the chamber <b>151</b> in the region(s) around the emitters <b>132</b> on the pedestal <b>133</b> between the optically transmissive members <b>149</b>, <b>150</b>. Phosphors in the wicking structure and/or fluid at <b>165</b> would be at the hot location from which the thermal conductivity and phase transition heat transfer mechanism <b>134</b> transfers heat.

0140As noted, the exemplary mechanism <b>134</b> also includes a working fluid <b>161</b> within the chamber <b>151</b>. The working fluid <b>161</b> is directly in contact with at least a portion of the opto-luminescent phosphor, in this example, within the wicking structure on one or both of the optically transmissive members <b>149</b>, <b>150</b>. The pressure within the chamber <b>151</b>, typically a pressure somewhat lower than atmospheric pressure, configures the working fluid <b>161</b> to absorb heat during operation of the lamp <b>111</b>, including heat from the phosphor produced by phosphor excitation and/or received from the solid state light emitters <b>132</b>. The working fluid <b>161</b>, in its liquid state, contacts the hot interface at the location <b>165</b> where the mechanism <b>134</b> receives or produces heat. In the example, the working fluid directly contacts at least some surface area(s) of the phosphor at or near the hot location <b>165</b>. When heated at the relatively hot location <b>165</b>, the working fluid <b>161</b> vaporizes. The vapor fills the chamber <b>151</b> and condenses at the cold location(s) <b>163</b>. At the cold location(s) <b>163</b>, heat is transferred from the vapor to the wall of the section <b>148</b> of the housing and from there to the heat sink <b>136</b> for dissipation to the ambient environment, typically to the atmosphere. The transfer of heat to the housing section <b>148</b> causes the vapor to condense back to the liquid form, at the relatively cold location(s) <b>163</b>. Through the capillary action of the wicking structure <b>160</b>, the liquid form of the working fluid <b>161</b> flows to the relatively hot location <b>165</b> around the emitters <b>132</b>. A variety of different fluids may be used as the working fluid, and the pressure is determined based on the fluid type and the amount of heat that the fluid is expected to transfer.

0141As in the earlier examples, the wicking structure <b>160</b> may take many forms, such as sintered metal, phosphor, glass or ceramic powder; woven copper; surface grooves, mesh arrangements or small closely spaced wires extending inward from the surfaces of the housing forming the walls of the chamber <b>151</b>; as well as nano-scale wire structures extending inward from the chamber surface(s); and various combinations of these forms. The spacing between elements of the wicking structure <b>160</b> is sufficiently small to cause inter-molecular forces on the liquid form of the working fluid <b>161</b> to cause the liquid to flow toward the region where the fluid vaporizes, that is to say, the hot location <b>165</b> in the mechanism <b>134</b>. This wicking or capillary action enables the liquid form of the working fluid to flow back to the hot location regardless of the orientation of (and thus the impact of gravity on fluid in) the heat transfer mechanism <b>134</b>.

0142In the example of <figref idref="DRAWINGS">FIG. 8</figref>, the mechanism <b>134</b> uses wicks for the structure <b>160</b> that utilize nanowires. A wick <b>162</b> formed on the inner surface of one or both of the optically transmissive members <b>149</b> and <b>150</b> utilizes nanowires that also include the phosphor, essentially like the nanowires in the example of <figref idref="DRAWINGS">FIG. 2D</figref>. The wick <b>164</b> formed on the inner surfaces of the thermally conductive housing section <b>148</b> in the example are metallic nanowires, which may be reflective, similar to the nanowire wick in the example of <figref idref="DRAWINGS">FIG. 2E</figref>. AS in the earlier example phosphors of multiple types may be provided, in the wick <b>162</b>, in different sections of the wick <b>162</b> or in the wick <b>162</b> and the working fluid <b>161</b>.

0143In operation, light energy from the emitters <b>132</b> pass through the optically transmissive members <b>149</b>, <b>150</b>. Some of that energy in an excitation band of the phosphor in the mechanism <b>134</b> excites the phosphor to emit light in an emission band that is at least somewhat different from the energy that excited the phosphor. Light produced by the phosphor excitation also passes through the optically transmissive members <b>149</b>, <b>150</b>. The combined light output of the lamp <b>130</b> through the bulb <b>131</b> typically will include some light from the emitters <b>132</b> as well as light produced by excitation of the phosphor. For example, the phosphor may convert some energy from a less desirable wavelength range (e.g. near or outside the visible spectrum) to a more desirable wavelength range (e.g. near or outside the visible spectrum) to a more desirable wavelength range (e.g. to fill-in a gap in the spectrum of the output of light engine <b>31</b> and/or to improve the quality of the light output).

0144<figref idref="DRAWINGS">FIG. 9</figref> shows an alternate example of a thermal conductivity and phase transition heat transfer mechanism, which may be used with other components similar to those of <figref idref="DRAWINGS">FIGS. 5 and 6</figref> to form a lamp. Instead of a separate mechanism <b>134</b> and bulb <b>131</b> as in the lamp of <figref idref="DRAWINGS">FIGS. 5 and 6</figref>, the mechanism <b>171</b> uses a transmissive member <b>173</b> to serve both as one of the optically transmissive members of the mechanism and as the outer bulb of the lamp.

0145As in the earlier examples, the mechanism <b>171</b> includes a housing <b>175</b> having a section <b>177</b> that is thermally conductive and two members <b>173</b> and <b>179</b> that are at least partially optically transmissive. The housing section <b>177</b> and the optically transmissive members <b>173</b> and <b>179</b> may be formed of materials and joined together to form a vapor tight chamber <b>181</b>, as in the earlier examples.

0146In this example, the thermally conductive housing section <b>177</b> is configured to connect with the modular coupling region of the heat sink <b>136</b> used for connection of the bulb in the example of <figref idref="DRAWINGS">FIG. 6</figref>. For that purpose, the section <b>177</b> has a downwardly extending circular boss <b>183</b> that mates with a corresponding groove or shoulder formed in the upper region of the heat sink.

0147The housing section <b>177</b> also is configured for connection to the two optically transmissive members <b>173</b> and <b>179</b>. The periphery <b>185</b> of the housing section <b>177</b> mates with a circular inner opening on the lower portion of the optically transmissive member <b>173</b>. The housing section <b>177</b> also includes an upwardly extending circular boss <b>185</b> that mates with the lower or proximal end of the inner optically transmissive member <b>179</b>.

0148When assembled and mounted on the heat sink, the inner optically transmissive member <b>179</b> is positioned around the straight section of the heat pipe, the pedestal and the light emitters in a manner similar to the mechanism <b>134</b> in the lamp example of <figref idref="DRAWINGS">FIG. 6</figref>. The outer optically transmissive member <b>173</b> is positioned around the member <b>179</b> and the other lamp elements in a manner similar to the bulb in the lamp example of <figref idref="DRAWINGS">FIG. 6</figref>. However, the connections of the members <b>173</b>, <b>179</b> to the housing section <b>177</b> form a sealed vapor chamber <b>181</b> for the thermal conductivity and phase transition heat transfer mechanism <b>171</b> in the space between the members <b>173</b> and <b>179</b>. The circular boss <b>183</b> of the housing section <b>177</b> is securely mounted on and/or bonded to the mating upper portion of the heat sink, to provide structural support for the mechanism <b>171</b> as well as to provide good thermal conductivity from the cold interface provided through the housing section <b>177</b> to the heat sink.

0149As in the earlier examples, the exemplary mechanism <b>171</b> also includes a working fluid <b>189</b> within the chamber <b>181</b>. The fluid <b>189</b> is a suitable type like, one of the fluids discussed earlier. The working fluid <b>189</b> is directly in contact with at least a portion of the opto-luminescent phosphor, in this example, within the wicking structure <b>191</b> on one or both of the optically transmissive members <b>173</b>, <b>179</b>. As in the previous lamp example, phosphor is provided in the wicking structure <b>191</b> on one or both of the optically transmissive members <b>173</b>, <b>179</b>, that is to say, in the same manner as in the wick discussed above relative to <figref idref="DRAWINGS">FIGS. 7 and 8</figref>. Phosphor may also be provided in the working fluid <b>189</b>. Detail A-A in <figref idref="DRAWINGS">FIG. 9</figref> represents an enlarged cross-sectional view of a portion of the optically transmissive outer member <b>173</b> with a section of the phosphor bearing wick <b>191</b> on the inner surface. Detail B-B in <figref idref="DRAWINGS">FIG. 9</figref> represents an enlarged cross-sectional view of a portion of the inner optically transmissive member <b>179</b> with a section of the phosphor bearing wick <b>191</b> on the outer surface.

0150Although not specifically shown, the wicking structure within the chamber <b>181</b> also includes a wick formed on the inner surface(s) of the thermally conductive section <b>177</b>. The wick on the section <b>177</b> may take any of the various forms discussed early, although for purposes of discussing a specific example, we will assume that the wick on the section <b>177</b> is formed of metallic nanowires which may be at least somewhat reflective, e.g. similar to the metallic nanowire wick discussed above relative to <figref idref="DRAWINGS">FIG. 2E</figref>.

0151The electrical and optical operations of the lamp that incorporates the mechanism <b>171</b> with the phosphor are essentially the same as those of the lamp of <figref idref="DRAWINGS">FIGS. 6-8</figref>. As in the other exemplary mechanisms, the pressure within the chamber <b>181</b>, configures the working fluid <b>189</b> to absorb heat during operation of the lamp that utilizes the mechanism <b>171</b>, including heat from the phosphor in the wicking structure <b>191</b> and any phosphor that may be provided in the working fluid, produced by phosphor excitation and/or received from the solid state light emitters. The working fluid <b>189</b>, in its liquid state, contacts the hot interface at the location around the upper distal end of the inner optically transmissive member <b>179</b> where the mechanism <b>134</b> receives or produces heat. In the example, the working fluid directly contacts at least some surface area(s) of the phosphor at or near the hot location and/or contains some of the phosphor(s). When heated at the relatively hot location, the working fluid <b>189</b> vaporizes. The vapor fills the chamber <b>181</b> and condenses at the cold location(s) at or around the inner surface of the thermally conductive section <b>177</b>. At the cold location(s), heat is transferred from the vapor to the wall of the section <b>177</b> of the housing and from there to the heat sink for dissipation to ambient environment, typically to the atmosphere. The transfer of heat to the housing section <b>177</b> causes the vapor to condense back to the liquid form, at the relatively cold location(s). Through the capillary action of the wick structure <b>191</b> and the wick (not shown) on the section <b>177</b>, the liquid form of the working fluid <b>189</b> flows to the relatively hot location.

0152The exemplary lamps discussed with respect to <figref idref="DRAWINGS">FIGS. 6-9</figref> produce a substantially omni-directional light output from the bulb or from the outer optically transmissive member, including through gaps or spaces between the heat sink fins. The principles under consideration here, however, are readily adaptable to other forms of lamps or fixtures providing different types of desired light output distributions. <figref idref="DRAWINGS">FIGS. 10-13B</figref> relate to a fixture of lamp where the one optically transmissive member of the various thermal conductivity and phase transition heat transfer mechanism that incorporates the phosphor also forms a directional optic, enabling the lamp or fixture utilizing the illustrated light emitting device to provide a field of output illuminated that is somewhat angularly limited.

0153<figref idref="DRAWINGS">FIGS. 10</figref>, <b>11</b> and <b>12</b> are top, isometric and side/plan views of the light emitting device <b>191</b>; and <figref idref="DRAWINGS">FIG. 13A</figref> is a cross-sectional view of the device <b>191</b>, and <figref idref="DRAWINGS">FIG. 13B</figref> is an enlarged view, showing details around the portion of the thermal conductivity and phase transition heat transfer mechanism <b>193</b> that incorporates a layer of phosphor <b>194</b>. Like the lamp <b>131</b> discussed earlier, the device <b>191</b> utilizes light emitting diodes (LEDs) <b>196</b> that serve as the source of optical energy for pumping the phosphor <b>194</b> within the mechanism <b>193</b>. In the example, there are six LEDs <b>196</b>, although there may be fewer LEDs or more LEDs, depending on the amount of optical energy required for a particular design/application for the device <b>191</b>. In addition to the LEDs <b>196</b> and mechanism <b>193</b> with the included phosphor <b>194</b>, the light emitting device <b>191</b> includes a heat sink <b>195</b> and a number of passive optical elements, to configure the device <b>191</b> for use in a fixture or lamp/light bulb for a more directed lighting application. One of the passive optical elements, the total internal reflection optic, also serves as the optically transmissive member <b>205</b>, as discussed in more detail, later.

0154As in the earlier examples, the light emitting device <b>191</b> may operate at any orientation, although a particular orientation is illustrated for convenience. Some aspects of the following description of the light emitting device <b>191</b> use directional terms corresponding to the illustrated orientation, for convenience only. Such directional terms but are not intended to be limiting in any way.

0155As illustrated, the mechanism <b>193</b> in the light emitting device <b>191</b> includes a housing having a section <b>203</b> that is thermally conductive and a member <b>205</b> that is at least partially optically transmissive. Although shown by way of example as a metal casing in <figref idref="DRAWINGS">FIG. 13A</figref>, as in the earlier examples, the thermally conductive section <b>203</b> of the mechanism housing may be made of a variety of other thermally conductive materials.

0156The thermally conductive section <b>203</b> consists of a hollow metal cylinder or tube having a circular cross-section. A substantial portion of the metal section <b>203</b> of the housing extends down into a hollow space and a proximal passage through the core <b>197</b> of the heat sink <b>195</b>. The copper section <b>203</b> may be press fitted into the passage or be otherwise connected and thermally coupled to the heat sink <b>195</b> in any appropriate manner suitable for efficient heat transfer and to provide structural support that may be necessary for the apparatus <b>193</b>. The end of the copper cylinder or tube of section <b>203</b> opposite the optically transmissive member <b>205</b> is closed, e.g. by a flat circular section of the metal casing.

0157The heat sink <b>195</b> is formed of a highly thermally conductive material, typically a metal such as copper or aluminum, although other materials, such as thermally conductive plastics and ceramics, may be used. The heat sink <b>195</b> in this example has a core <b>197</b> and radially extending fins <b>199</b>. Straight radial fins are shown at <b>199</b>, for convenience, although other shapes/contours may be used for the fins, e.g. to improve transfer of heat to the ambient atmosphere.

0158The heat sink core <b>197</b> has a cylindrical central hollow space surrounding most of the housing section <b>203</b>, although in this example, the wall of the central space does not directly contact the housing of the mechanism <b>193</b>. A proximal end (lower end in the drawings) of the heat sink <b>193</b> closes the hollow space in the core except for a central passage, a wall of which forms a fairly tight structural and thermal connection to the outer surface of proximal end of the thermally conductive section <b>203</b> of the housing of the mechanism <b>193</b>. A more extensive close fitting connection between the heat sink <b>195</b> and more or all of the length of the housing section <b>203</b> could be provided. As noted, the housing section <b>203</b> may be press fitted into the central passage or bonded to the heat sink <b>195</b>, for example by soldering, welding or an appropriate adhesive.

0159The connection of the housing section <b>203</b> in the passage through the proximal end of the heat sink core provide structural support for the housing section <b>203</b> as well as thermal conductivity from the mechanism <b>193</b> to the heat sink <b>195</b>. The connection thus configures the proximal end of the housing section <b>203</b> as the cold interface of the thermal conductivity and phase transition heat transfer mechanism <b>193</b>.

0160In this example, the optically transmissive member <b>205</b> is itself a passive optical processing element, formed of a material and shaped to provide total internal reflection (TIR) with respect to light passing through the material of the optic impacting at certain angles with respect to surfaces of the TIR optic formed by the member <b>205</b>. The example shows the member in the shape of a truncated circular cone with a tapered conical outer lateral surface, and a flat circular distal end surface, although other shapes may be used. The member <b>205</b> may be formed of glass, plastic or other similar materials of appropriate optical properties.

0161A separate member could be used as the optically transmissive member, and the TIR optic would be fitted over the separate member. However, in the illustrated example, the material of the TIR optic also serves the optically transmissive member <b>205</b> of the thermal conductivity and phase transition heat transfer mechanism <b>193</b>. As shown in <figref idref="DRAWINGS">FIGS. 13A</figref>, <b>13</b>B with the TIR optic/member <b>205</b>, a hollowed portion of the optic forms a portion of the inner wall of the housing and thus part of the chamber <b>206</b> of the thermal conductivity and phase transition heat transfer mechanism <b>193</b>. It should be noted that the detail view of <figref idref="DRAWINGS">FIG. 13B</figref> represents only the portion of the optic/member <b>205</b> encircled by the arrow B-B and does not show the entire TIR optic <b>205</b> (compare to <figref idref="DRAWINGS">FIG. 13A</figref>).

0162In this example, the optically transmissive member <b>205</b> has a hollow cylinder or tube formed within the material of the TIR optic <b>205</b> for forming the vapor chamber <b>206</b> when joined to the housing section <b>203</b>. The hollow section has a circular cross-section and is closed at one end by a curved or dome-shaped contour within the glass, although other shapes for this chamber section could be used. The interior of the cylindrical thermally conductive section <b>203</b> and the hollow within the optically transmissive member/optic <b>205</b> have approximately the same lateral dimensions so as to form a relatively straight continuous cylindrical volume for the vapor chamber <b>206</b> within the housing.

0163The optically transmissive member <b>205</b> is connected to the metal casing that forms the thermally conductive section <b>203</b> to form a housing enclosing the vapor chamber <b>206</b> and the phosphor <b>194</b>. Specifically, the section <b>203</b> and member <b>205</b> are connected so as to form a vapor tight seal for the chamber <b>206</b>. Depending on the materials used for components <b>203</b> and <b>205</b> of the mechanism, the two components <b>203</b> and <b>205</b> may be joined by a glass fit process or by application of a suitable epoxy, at the metal/optic interface.

0164The thermal conductivity and phase transition heat transfer mechanism <b>193</b> also includes an opto-luminescent phosphor <b>194</b> contained within the chamber <b>206</b> for emitting light when excited by optical pumping energy. In this example, the phosphor takes the form of a layer at <b>194</b> formed on the inner surface of the hollowed portion of the TIR optic/member <b>205</b> that forms a portion of the inner wall of the chamber <b>206</b> within the optic <b>205</b>. The phosphor <b>194</b> is the active optical element of the mechanism <b>294</b>. The material of the phosphor <b>194</b> is the same as discussed above with regard to earlier examples. The heat transfer function of the mechanism <b>193</b> mitigates thermal impact on the phosphor <b>194</b>.

0165The thermal conductivity and phase transition heat transfer mechanism <b>193</b> also includes a working fluid, of one of the types discussed in the earlier examples. The working fluid, in its liquid state, contacts the hot interface at the location where the apparatus receives or produces heat. In the example, the working fluid directly contacts at least some surface area(s) of the phosphor layer <b>194</b> through the wicking structure at or near the hot location. At those surface areas, the working fluid absorbs at least some heat from the phosphor <b>194</b>, be it heat generated by excitation of the phosphor or heat the phosphor may receive from the operation of the LEDs <b>196</b>.

0166As in the earlier examples, the device <b>191</b> of <figref idref="DRAWINGS">FIGS. 13-15</figref> includes a wicking structure <b>208</b> mounted within the chamber <b>206</b> to facilitate flow of condensed liquid of the working fluid from the cold location to the hot location. Together, the housing, the chamber, the working fluid and the wicking structure form a thermal conductivity and phase transition heat transfer mechanism <b>193</b> for transferring heat away from the phosphor <b>194</b>. In this case, with the phosphor <b>194</b> formed as a layer on the inner surface of the optic/member <b>205</b>, light from the emitters that passes through the phosphor as well as light emitted toward the chamber <b>206</b> by phosphor excitation should be directed out through the optic/member <b>205</b>. For that purpose, at least the portion of the wicking structure formed on the inner surface of the hollowed portion of the TIR optic/member <b>205</b> that forms a portion of the inner wall of the chamber <b>206</b> is reflective. For example, at least that portion of the wicking structure <b>208</b> may be formed of reflective metallic nanowires or a reflective mesh. Of course, other reflective wicks may be used. The portion of the wicking structure <b>208</b> on the inner surfaces of the thermally conductive housing section <b>203</b> may be similarly formed of metallic materials or may be formed of one of the other types of wicks discussed earlier.

0167The working fluid directly contacts the outer surfaces of the phosphor layer <b>194</b>, e.g. through gaps between the nanowires forming the portion of the wick <b>208</b> on the inner surface of the phosphor <b>194</b>. The pressure within the chamber configures the working fluid to absorb heat from the phosphor <b>194</b> during operation of the device <b>191</b>, to vaporize at a relatively hot location at or near the phosphor <b>194</b> as the working fluid absorbs heat. The vapor transfers heat to and condenses at a relatively cold location of the copper section in contact with the heat sink <b>195</b>, and the condensed working fluid returns as a liquid to the relatively hot location at or around the phosphor <b>194</b>.

0168As in several earlier examples, the LEDs <b>196</b> are separate and apart from the phosphor <b>194</b> within the mechanism <b>193</b>, and as a result, the phosphor is remotely deployed relative to the LEDs <b>196</b>. The LEDs are additional active optical processing elements, in this case outside of the mechanism <b>193</b>, for supplying the pumping energy to the phosphor <b>194</b>. The LEDs <b>196</b> are mounted around the inner circumferential surface of an outer ring of an LED support <b>198</b>. In addition to the ring, the LED support <b>198</b> includes a circular plate for attachment to the heat sink <b>195</b>. The LED support <b>198</b> is formed of a thermally conductive material similar to the materials used for the heat sinks and/or for the thermally conductive housing sections in the earlier example. The LED support <b>198</b> provides structural support for the LEDs <b>196</b> as well as thermal conductivity to transfer heat from the LEDs <b>196</b> to the upper surface of the heat sink, for dissipation to the ambient environment, that is to say to atmosphere in the present example. In the example, the LEDs emit optical energy in a spectral range below 420 nm, that is to say, in the near UV range or the UV range.

0169Each of the LEDs <b>196</b> is oriented with its respective axis of emission aligned at least substantially along a radius of the device <b>191</b>, to direct emitted light inward along the radius toward the central axis of the device <b>191</b>. To provide an efficient coupling of light from each LED into the optic <b>205</b>, the device <b>191</b> includes a collimating optic <b>209</b> for each LED <b>196</b>. The collimating optic <b>209</b> fits between the optical output of the respective LED <b>196</b> and a dichroic filter <b>210</b>, and the dichroic filter <b>210</b> in turn is positioned against the exterior surface of the TIR optic <b>205</b>.

0170Each collimating optic <b>209</b> may be formed of a transparent material such as an appropriate glass or plastic, which provides a high optical transmissivity with respect to light from the LEDs <b>196</b>. The optic <b>209</b> is configured to reflect light within the optic back from its lateral surfaces towards the exit surface at the interface with the dichroic filter <b>210</b>. For that purpose, the lateral surface of each collimating optic <b>209</b> with a material providing an inward facing reflector, or the outer surface may be treated or otherwise configured to reflect light by total internal reflection. In this way, the optic <b>209</b> collimates light from the respective LED and directs substantially all of that light for output to the dichroic filter <b>210</b>.

0171Each collimating optic <b>209</b> may be formed with an indentation and matching inner surface for accepting light from the respective LED <b>196</b>. The configuration of the collimating optic <b>209</b> may provide close proximity or contact with the LED output, although an optical gel or adhesive may be provided for index of refraction matching, to insure efficient light output. A similar gel or adhesive may be used at the optical coupling of the collimating optic <b>209</b> to the dichroic filter <b>210</b> and/or between the dichroic filter <b>210</b> and external surface of the TIR optic <b>205</b>.

0172A dichroic filter <b>210</b> passes light in a first wavelength band and reflects light outside that wavelength band. In this example, the dichroic filters <b>210</b> pass light below 420 nm and reflect light at or above 430 nm. The LEDs <b>196</b> emit optical energy in the near UV or UV (ultraviolet) range. Hence, in the illustrated arrangement, the dichroic filters <b>210</b> allow light from the LEDs <b>196</b> to pass through at a relatively high incident angle with respect to the outer surface of the TIR optic <b>205</b> and thus enter the optic <b>205</b>.

0173The LEDs <b>196</b> are arranged and the collimating optics <b>209</b> are configured so that most of the light from the LEDs <b>196</b> are directed at least substantially radially inward, that is to say, so as to impact the phosphor layer <b>194</b> in the mechanism <b>193</b> located in the lower portion of the optic <b>205</b> at and around the central axis of the light emitting device <b>191</b>. Any light entering the optic <b>205</b> from the LEDs <b>196</b> and the collimating optics <b>205</b>, which may be directed down toward the lower face of the optic <b>205</b>, may be reflected upward by total internal reflection to insure most such light reaches the phosphor <b>194</b>.

0174The phosphor in this example comprises one or more opto-luminescent materials of a type excited by optical energy in a range that includes at least a substantial portion of the wavelength range of the emissions from the LEDs <b>196</b>, in this case light in the near UV and/or UV range. Stated another way, the rated wavelength of emissions of the LEDs <b>196</b> falls within the excitation spectrum of the phosphor material(s). For example, the LEDs may be near UV LEDs, such as LEDs rated to emit 405 nm near UV light; and in such a case, the excitation spectrum of each phosphor material in the layer <b>194</b> would include 405 nm. The dichroic filters <b>210</b> allow 405 nm light from the LEDs to enter the optic <b>205</b> to reach and excite the phosphor at <b>194</b>. The phosphor in turn emits light if one or more different spectra, in response to the 405 nm excitation energy. For example, a combination of three or more broad emission spectra phosphor materials may be excited together to provide a combination of spectra that together approximate white light of a desirable characteristic.

0175The light produced by excitation of the phosphor <b>194</b>, either directly or upon reflection from the reflective wick, passes back into the TIR optic <b>205</b>. Most if not all of the light produced by the excitation of the phosphor will be in the range above 430 nm. Hence, any such light that goes back toward the dichroic filters <b>210</b> will be reflected by the dichroic filters <b>210</b>. Excitation light reaching the lateral surface of the TIR optic <b>205</b> at relatively shallow angles will be reflected by total internal reflection toward the output surface, the top surface in the illustrated orientation. Light emitted or reflected toward the output surface, however, will reach that surface at a relatively steep angle with respect to that surface and therefore will pass through as an output of the device <b>191</b>.

0176During this operation of the light emitting device <b>191</b>, the ring <b>198</b> transfers heat generated by the LEDs <b>196</b> to the heat sink <b>195</b> for dissipation. The operation of the thermal conductivity and phase transition heat transfer mechanism <b>193</b> transfers heat from the phosphor and the proximal end of the optic <b>205</b> through the cold interface to the heat sink <b>195</b> for dissipation.

0177The examples outlined above have provided remote phosphor deployments with respect to the source, for example, where the phosphor is in a mechanism outside of or separate from the package that include the chip of the solid state device(s) forming the source. It is also contemplated that the phosphor and the source both may be included within the thermal conductivity and phase transition heat transfer mechanism. It may be helpful to consider some examples. Although the source may be a semiconductor chip or other device inside the mechanism, we will use an example in which the semiconductor light emitter is formed of nanowires that also serve as a portion of the wick.

0178<figref idref="DRAWINGS">FIG. 14</figref> is a top view, and <figref idref="DRAWINGS">FIG. 15</figref> is an isometric view, of a device or light engine for emitting light. The illustrated device <b>301</b> could be used as a light engine of a light fixture, although the exemplary configuration is particularly configured for use in a lamp or ‘light bulb,’ for example, in combination with a transparent, translucent or colored transmissive globe like the globe in the example of <figref idref="DRAWINGS">FIGS. 5 and 6</figref> but not shown here for convenience.

0179As in the earlier examples, the light emitting device <b>301</b> may operate at any orientation, although a particular orientation is illustrated for convenience. Some aspects of the following description of the light emitting device <b>301</b> use directional terms corresponding to the illustrated orientation, for convenience only. Such directional terms may help with understanding of this description of the example of <figref idref="DRAWINGS">FIGS. 14-16B</figref> but are not intended to be limiting in any way.

0180The light emitting device <b>301</b> includes a light emitter that is integrated with a thermal conductivity and phase transition heat transfer mechanism, represented together as one integral element <b>303</b> in the drawings. The mechanism <b>303</b> also includes a phosphor <b>325</b>, as discussed in more detail, later. Heat is transferred from the apparatus <b>303</b> to a heat sink <b>305</b>. The heat sink <b>305</b> is formed of a highly thermally conductive material, typically a metal such as copper or aluminum, although other materials, such as thermally conductive plastics and ceramics, may be used. The heat sink <b>305</b> in our example has a core <b>307</b> having a central passage, a wall of which forms a fairly tight structural and thermal connection to the outer surface of a portion of the housing of the apparatus <b>303</b>. The rest of the apparatus <b>303</b> extends upward or away from the passage in the core <b>307</b> of the heat sink <b>305</b>, to form a pedestal or the like with a light emitting diode at or near the distal end. Extending radially outward from the core <b>307</b>, the heat sink <b>305</b> has a number of fins <b>309</b> for radiating heat to the ambient atmosphere. Straight radial fins are shown, for convenience, although other shapes/contours may be used, e.g. to promote heat transfer and/or to allow a desired amount of light from the emitter and phosphor to pass down between the fins.

0181<figref idref="DRAWINGS">FIG. 16A</figref> is a cross-sectional view taken along line A-A of <figref idref="DRAWINGS">FIG. 14</figref>, and <figref idref="DRAWINGS">FIG. 16B</figref> is an enlarged detail view of a portion of the optical/electrical emitter <b>303</b> and heat sink <b>305</b> corresponding to that encircled by the arrow B-B in <figref idref="DRAWINGS">FIG. 16A</figref>. As illustrated, the light emitting device <b>301</b> includes a housing having a section <b>313</b> that is thermally conductive and a member <b>315</b> that is at least partially optically transmissive. In this example, the thermally conductive section <b>313</b> consists of a hollow copper cylinder or tube having a circular cross-section. A substantial portion of the copper section <b>313</b> of the housing extends down into the passage through the core <b>307</b> of the heat sink <b>305</b>. The copper section <b>313</b> may be press fitted into the passage or be otherwise connected and thermally coupled to the heat sink <b>305</b> in any appropriate manner suitable for efficient heat transfer and to provide structural support that may be necessary for the apparatus <b>303</b>. The end of the copper cylinder or tube of section <b>313</b> opposite the optically transmissive member <b>315</b> is closed, e.g. by a flat circular section of copper.

0182In this example, the optically transmissive member <b>315</b> consists of a hollow glass cylinder or tube having a circular cross-section and closed at one end by a curved or dome-shaped section of the glass. The cylindrical thermally conductive section <b>313</b> and the optically transmissive member <b>315</b> have approximately the same lateral dimensions so as to form a relatively straight continuous cylinder, although other lateral and cross-sectional shapes could be used. For example, one or both of the elements <b>313</b>, <b>315</b> could vary in shape and/or dimension along the lateral length of the light emitter <b>303</b>, e.g. so that the region away from the heat sink <b>305</b> is somewhat enlarged or bulbous at the end of the pedestal. Also, the distal end of the optically transmissive member <b>315</b> (furthest away from the heat sink <b>305</b>) could have other shapes, e.g. to be flat or concave instead of the illustrated dome shape.

0183The glass optically transmissive member <b>315</b> is connected to the copper thermally conductive section <b>313</b> of the light emitter <b>303</b> to form a housing enclosing a vapor chamber, a semiconductor light emitting device and a phosphor <b>325</b>. Specifically, the section <b>313</b> and the member <b>315</b> are connected so as to form a vapor tight seal for the chamber. The two elements may be joined by a glass frit process or by application of a suitable epoxy, at the glass/copper interface.

0184Glass and copper are given by way of examples of the materials of the optically transmissive member <b>315</b> and the thermally conductive section <b>313</b>. Those skilled in the art will appreciate that other optically transmissive materials and thermally conductive materials may be used.

0185The semiconductor light emitting device in this example includes semiconductor nanowires forming a light emitting diode (LED) <b>317</b>, within the chamber. In this example, the semiconductor nanowires forming the LED <b>317</b> are formed or mounted on the curved interior surface at the distal end of the optically transmissive member <b>315</b>.

0186<figref idref="DRAWINGS">FIG. 17</figref> shows an example of a section of the LED type semiconductor light emitting device <b>317</b>, utilizing semiconductor nanowires <b>327</b> in portion <b>323</b><i>a </i>of the wicking structure <b>323</b>. As discussed herein, applicable semiconductor light emitters essentially include any of a wide range light emitting or generating devices formed from organic or inorganic semiconductor materials.

0187The light emitting device <b>318</b> formed using the semiconductor nanowire wick <b>317</b>, includes a conductive base <b>335</b>. The base may be formed of an appropriate conductive material, in this case, over the phosphor layer <b>325</b>. For an arrangement like that of <figref idref="DRAWINGS">FIGS. 16B and 17</figref>, where the emitter <b>317</b>, <b>318</b> is adjacent to the phosphor layer <b>325</b> on the optically transmissive member <b>315</b>, the conductive base <b>335</b> may also be optically transmissive. For example, the conductive base <b>335</b> can be formed of Indium Tin Oxide (ITO), other similar transparent conductive oxides, transparent conducting polymers, or layers consisting of transparent carbon nanotubes. In the example of <figref idref="DRAWINGS">FIG. 17</figref>, the transparent conductive base <b>335</b> is formed on the phosphor <b>325</b>. Although not separately shown in <figref idref="DRAWINGS">FIG. 17</figref>, an electrical connection will be provided to the base <b>335</b>, e.g. by one of the leads shown in <figref idref="DRAWINGS">FIG. 15</figref>, to provide one of the current path couplings to the semiconductor light emitter <b>317</b>.

0188The light emitter <b>318</b> also includes nanowires <b>327</b> grown to extend out from the conductive base <b>335</b> to form elements of the wick <b>317</b>. Each individual semiconductor nanowire <b>327</b> in the example includes an inner nanowire <b>329</b> as a core and an outer nanowire <b>331</b>. The inner and outer nanowires are doped with different materials so as to be of different semiconductor types. In the example, the inner nanowire <b>329</b> is an N type semiconductor, and the outer nanowire <b>331</b> is a P type semiconductor, although obviously, the types could be reversed. As a result of the semiconductor growth and doping processes, there is semiconductor junction or intrinsic region <b>333</b> formed between the two semiconductor type nanowires <b>329</b>, <b>331</b>. In the example, the material forming the intrinsic region and the P type semiconductor also extends over the inner surface(s) of the conductive base <b>335</b> between the N type inner nanowires <b>329</b>. Those skilled in the art will recognize that the doping may be applied so as to essentially reverse the semiconductor types, e.g. so that the inner core nanowire <b>329</b> is a P type semiconductor and the outer nanowire <b>331</b> is an N type semiconductor.

0189Although not shown, reflectors may be provided at the distal ends (away from the base <b>335</b>) of the semiconductor nanowires <b>327</b> to direct more of the light produced by the nanowire diodes back through the base <b>335</b>, the phosphor <b>325</b> and the curved distal section of the light transmissive member <b>315</b>.

0190<figref idref="DRAWINGS">FIG. 17</figref> also illustrates some of the working fluid <b>335</b> of the phase transition cycle of the heat transfer mechanism. The working fluid <b>335</b> directly contacts the outer surface(s) of at least the nanowires <b>327</b> of the semiconductor transducer, so that the fluid <b>335</b> may efficiently absorb heat from the emitter <b>318</b> during operation of the transducer. The working fluid may also directly contact at least some surface areas of the phosphor <b>325</b>, for example, through vias formed through the semiconductor layers and base on the light emitting device <b>318</b>. As noted, the conductive base <b>25</b> provides one of the electrical connections to the semiconductor nanowires <b>27</b>, in this example, to the N type semiconductor inner nanowires <b>329</b>. Although the electrical connection to the P type semiconductor outer nanowires <b>331</b> could be provided via the working fluid <b>335</b>, other types of electrical connections to the outer nanowires <b>331</b> could be provided, e.g. in the form of one of the leads in the example of <figref idref="DRAWINGS">FIG. 15</figref>.

0191For an electrical-to-optical energy conversion, like the light emitting device <b>301</b> of <figref idref="DRAWINGS">FIGS. 14-15A</figref>, the inner and outer nanowires together form a light emitting diode. A voltage is applied to produce a drive current through the diode. Application of a voltage at or above the diode turn-on threshold, across the P-N junction at the intrinsic region <b>333</b>, causes each of each of the nanowires <b>327</b> to produce light.

0192The discussion of <figref idref="DRAWINGS">FIG. 17</figref> to this point focused on the semiconductor structure of the transducer <b>317</b> within the chamber and the light emitter operation. However, the nanowires <b>327</b> also form part of the wicking structure <b>317</b> of the combined phase transition and heat transfer mechanism. The spacing between the nanowires <b>327</b> is sufficiently small so as to facilitate capillary action on the working fluid <b>35</b>, so that the nanowires <b>27</b> also function as portion of the wicking structure in the mechanism <b>303</b> of <figref idref="DRAWINGS">FIGS. 14-16B</figref>. Other portions of the overall wicking structure are discussed more, later.

0193The glass forming the optically transmissive member <b>315</b> may be transparent or translucent or exhibit other transmissive characteristics (e.g. non-white color filtering), depending on the application for the device <b>301</b>. The glass of the member <b>315</b> permits emission of at least some light from the LED <b>317</b> as an output of the light emitting device <b>301</b>.

0194For purposes of operating as a thermal conductivity and phase transition heat transfer mechanism, the light emitting device <b>301</b> also includes a working fluid within the chamber. The working fluid directly contacts the outer surfaces of the nanowires of the LED wicking structure <b>317</b> and may contact at least some surface(s) of the phosphor layer <b>325</b> through gaps or vias through the semiconductor structure between the individual nanowires. The pressure within the chamber configures the working fluid to absorb heat from the LED <b>317</b>, particularly from the nanowires, during operation of the device <b>301</b>. The fluid vaporizes at a relatively hot location at or near the semiconductor nanowires of the LED <b>317</b> as the working fluid absorbs heat. The vapor transfers heat to and condenses at a relatively cold location of the copper section <b>313</b> in contact with the heat sink <b>305</b>, and the condensed working fluid returns as a liquid to the relatively hot location at or around the LED <b>317</b>.

0195As in the earlier examples, the device <b>301</b> of <figref idref="DRAWINGS">FIG. 14</figref> includes a wicking structure mounted within the chamber to facilitate flow of condensed liquid of the working fluid from the cold location to the hot location. Together, the housing, the chamber, the working fluid and the wicking structure form a thermal conductivity and phase transition heat transfer mechanism for transferring heat away from the LED <b>317</b>, in this case, to the heat sink <b>305</b>. The semiconductor nanowires of LED <b>317</b> on the inner curved surface of the glass member <b>315</b> are configured to serve as a portion of the wicking structure.

0196In addition to the nanowire wick <b>317</b> of the LED, the wicking structure includes a non-LED (not semiconductor nanowires) wick <b>321</b> formed on the portions of the inner surface of the glass member <b>315</b> in regions other than the region(s) covered by the structure of the LED <b>317</b>. The overall wicking structure further includes a non-LED (not semiconductor nanowires) wick <b>323</b> on the inner surface of the copper section <b>313</b>. The wicks <b>321</b> and <b>323</b> may take many forms, as discussed above with regard to various earlier examples. The wicks may be similar to each other or different. In the example of <figref idref="DRAWINGS">FIGS. 14-16B</figref>, the non-LED wick <b>321</b> in the glass member <b>315</b> may be formed of a material that is at least somewhat optically transmissive, whereas the non-LED wick <b>323</b> in the copper section <b>313</b> may be at least somewhat reflective.

0197As outlined earlier, the light emitting device <b>301</b> include a phosphor layer <b>325</b> between the LED <b>317</b> and the curved interior surface at the distal end of the optically transmissive member <b>315</b> on which the LED is mounted. Light emerging from the LED <b>317</b> toward the curved interior surface of the optically transmissive member <b>315</b> passes through the phosphor layer <b>325</b>. Some of the light excites the phosphor, and the excited phosphor converts optical energy from the LED <b>317</b> from energy in one wavelength range (the excitation band of the phosphor) to another wavelength range. For example, the phosphor <b>325</b> may convert some energy from the LED <b>317</b> from a less desirable wavelength range (e.g. near or outside the visible spectrum) to a more desirable wavelength range (e.g. to fill-in a gap in the spectral characteristic of light produced by the emitter), to improve efficiency of the light emitting device <b>301</b> and/or to improve the quality of the light output.

0198The phosphor layer <b>325</b> may include one type of phosphor or phosphor of a number of types, depending on the desired characteristics of the light output of the device <b>301</b>. Also, the phosphor layer may extend down the inner surface of the housing, e.g. down the inner cylindrical surface of the glass member <b>315</b> to the glass/copper interface. Additional phosphor may be provided in the working fluid.

0199<figref idref="DRAWINGS">FIG. 18</figref> is a top view, and <figref idref="DRAWINGS">FIG. 19</figref> is an isometric view of another device or light engine <b>301</b>′ for emitting light. <figref idref="DRAWINGS">FIG. 20A</figref> is a cross section view taken along line A-A of <figref idref="DRAWINGS">FIG. 18</figref>, and <figref idref="DRAWINGS">FIG. 20B</figref> is an enlarged detail view of a portion of the optical/electrical emitter and heat sink of <figref idref="DRAWINGS">FIG. 20A</figref>, showing the addition of a phosphor layer. The device or light engine <b>301</b>′ is generally similar to the device <b>301</b> of <figref idref="DRAWINGS">FIGS. 14-16A</figref>, like reference numerals identify corresponding elements, and the discussion above can be referenced for detailed information about the corresponding elements. The device <b>301</b>′ does include a phosphor. However, instead of including the phosphor as a layer between the light emitting diode and the surface of the optically transmissive member <b>315</b>, the phosphor in the device <b>301</b>′ is carried by the working fluid <b>325</b>′. A phosphor bearing working fluid as may be used in the device <b>301</b>′ has been discussed earlier with regard to earlier examples.

0200Those skilled in the art will appreciate that the teachings above may be applied in a variety of different ways and are not limited to the specific structures, materials and arrangements shown in the drawings and described above. For example, each of the instructed devices includes one thermal conductivity and phase transition heat transfer mechanism that incorporates phosphor. It is contemplated that a single light emitting device or apparatus may include multiple thermal conductivity and phase transition heat transfer mechanisms each with phosphor included therein.

0201It should be apparent from the discussion above that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting,” etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements or spacing may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element, there are no intervening elements present, although in some cases there may be intervening elements or layers of up to a micron or so, so long as such layers or elements do no substantially reduce thermal conductivity. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that are nearby or even overlap or underlie the adjacent feature.

0202Similarly, spatially relative terms, such as “under,” “below,” “lower,” “over,” “upper” related orientation or directional terms and the like, that may have been used above for ease of description to describe one element or feature's relationship to another element(s) or feature(s) orientation or direction as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features.

0203While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.